THERE  IS NO  BETTER WAY TO STATE  IT–

LAWSEN WAS A FANATACIST WHEN IT  CAME  TO BELIEVING  IN  PREDICTIBLE DISEASE CYCLES.

To be able to predict a natural  rhythm or  cycle was a mathematicians’ dream.

It pretty much guaranteed you fame,  at  least  for  the remaining  years of your career.

The reason I post this article is simply to provide an example of how wrapped up researchers sometimes get in their theories. Known as Occam’s Razor effect, this behavior not only happens to individuals, but also to professions in general. Theories and hypotheses in general are often subjected to this human behavior. Total political and social movements can develop due to these behaviors.

A medical disease cartographer I cover elsewhere on this site, Robert Felkin, is an example of such a follower. He uses Lawson’s theory to explain the disease maps he published.

Felkin had many opportunities to travel the earth due to professional and personal relationship with the African missions movement. The results of his engagement in these activities included observations he made of the diseases that were prevalent abroad, but rare in Western Europe. Like others during this time, this led Felkin and many others to draw conclusion from these observations that in the long run assigned the blame for some serious diseases and African culture, African traditions, and even the location of Africa itself on the planet.

The concept of the Aryan race became popular during these years, as the works of Charles Darwin generated its evolutionary theory and an implied one ancestor hypothesis for the evolution of man. Anti-evolutionists who were adamantly against this single race theory used the physical nature of the two parts of the earth that appeared negro-dominated versus Causasian-dominated to argue their claim.

Lawson’s observations about the different behaviors or effects of magnetic energy on the earth itself, and the influx of this energy from other parts of the solar system or universe at large, gave Lawson the observations he needed to base certain parts of his theory upon.

It is a normal part of human nature to want to believe that you are right and/or that some basic observations your have made support your hypothesis or theory as to why things behave the way they do. When such a point is reached in the intellectual world, we have a hard time reversing that foundation of knowledge which define those theories or hypothesis most important to us. This is the reason why, with medicine, some treatments that develop such a big following may continue to be used for quite some time, undergo some hypothetical changes due to another new discovery, but ultimately fail in the long run and slowly and quietly fade away.

Other examples of this behavior regarding disease patterns and cyclicity prevailed with cholera as well. Returning celestial objects like comets and meteors were often blamed, along with the recurring solar flares and sunspot cycles. Even commerce and international trade were considered potential victims of Mother Nature’s many ways of expressing rage.

One of the things to look for in these kinds of writings is how the author argues for the exceptions to the rule. These slight differences are often blamed on exceptions, like some magnetic anomaly, or the fact that only eucalyptus trees are growing there, or the fact that the oranges are less acidic than they normally are.

Sometimes in health care, “we are what we think we are, or perceive ourselves to be”. When psychosomaticism becomes the cause, existentialism and beliefs are the means to the cure, or lack there of.

Preliminary note: Although I opened this page for readers to review, please note the article is still in serious need of proofing and especially review of the tables that are either lacking or were poorly converted into text data.

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MEDICAL REPORT FOR  1864  (441-471)

FURTHER OBSERVATIONS ON PANDEMIC WAVES.

Shewing their Period, Limits, and Rate of Progress, and their connection with Terrestrial Magnetism.

By Robert Lawsen, Esq., Deputy Inspector-General of Hospitals.

A Paper appeared in the Sanitary Report of the Army for 1861, in which I drew attention to the connection of the successive outbreaks of fever in various parts of the world with a series of waves proceeding, at intervals of a few years, from the southern to the northern hemisphere. From the extent these embraced in longitude, and the length and regularity of their course, they evidently depended on some general law, which, as their progress seemed uninfluenced by atmospheric currents, was most probably terrestrial. As the

MEDICAL REPORT FOR 1864. 441

waves reached a higher latitude in Europe than in North America at the same time, the position of the magnetic pole, close to the north of the latter, suggested the connection with magnetism. The paper must be regarded, however, as little more than a preliminary enquiry, in which the existence and course of the waves was recognized without their period and limits being defined, or any attempt made to trace them to their causes. The object of the present communication is to afford information on these points, as far as the materials in my possession seem to authorize.

I. The Period of the Wave.

If the records of disease at any place where fever constitutes a material portion of the sickness be examined, it will be found that, for the most part, the serious outbreaks occur either in the odd or in the even years, according to its geographical position. There may be epidemics in the alternate years, but far more frequently they show themselves in the year peculiar to the station. Thus, at Sierra Leone there were some cases of yellow fever in 1817, a severe epidemic in 1823, another in 1839, one case in 1835, a severe epidemic in 1837, three cases in 1845, another severe epidemic in 1847, and again another in 1859, all of them odd years. In Jamaica there were very severe epidemics of yellow fever in 1819, 1825, 1827, 1831, 1837, 1841, 1853; there has been considerable mortality in the even years, occasionally from fever, but as will be shown hereafter the excess fell on the odd years. Yellow fever appeared at Gibraltar in 1804, 1810, 1813, 1814, 1828, besides threatening to do so on several other occasions; of the five periods thus given four are even years, and one only an odd year. These facts show the waves to have a period of two years, or of some multiple of that; but, on the whole, the two yearly period seems to represent them best.

In the former paper a Table was inserted giving the millesimal ratios of mortality among the troops, each year, at the various military stations for which the records were available. To facilitate reference the same information has been repeated here, but differently arranged, and with the mortality from acute and chronic dysentery and diarrhoea added. These affections of the bowels, though distinguished from each other in the returns, and often sufficiently marked in practice, yet, at other times, pass into each other in such a manner that, in the present enquiry, it is better to class them together than, for the sake of apparent exactness, to separate complaints which in many instances seem to be intimately connected.

Table I contains the annual millesimal ratios of the deaths from fever, and from diarrhoea and dysentery, the data for which are given in the Statistical Reports on the Mortality in the Army from 1817 to 1846. Up to 1836 the returns for the year were closed on 20th December, subsequently they were made up from 1st April to 31st March in the following year, l’he months embraced in the year, therefore, differ in the two periods, but as the sickly season amongst the troops in the Mediterranean and American stations (as will be shown below) does not commence before May or June, no error of consequence will arise from comparing the ratios for the period 1837-46 with those for the preceding one 1817-36.

Table II embraces ratios deduced from data obtained from various sources, and the admissions into various fever hospitals in the United Kingdom, and the Seraphim Hospital in Stockholm. The ratios for the Navy on the Coast of Africa embrace the deaths from all diseases ; but as all were from fever except about 200 per 1,000 of strength* by deducting this number from the figures in the Table, the actual loss from fever may be obtained very nearly. In Edinburgh the returns of admissions of fever cases were closed on 31st December each year, to 1825 exclusive; subsequently they were made up to 30th September, so that 1826 gives the admission for nine months only, and then for the subsequent years anticipate the end of the year by three months from which it results that the sickness during the last quarter of each is thrown into that of the following one, increasing it unduly, and reducing that for the current one to a corresponding extent. This will account, in part at least, for the admissions in the even years, the second year of the waves at Edinburgh, exceeding so much those in the odd years subsequent to 1826.

* Bryson, Climate and Principal Diseases of African Station, p. 178.

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In Table II the mortality for all the odd years, at each station, has been added together, and the mean taken, and similarly for the even years, and it will be seen that in every case it is greater in one or other, and that, generally, the excess of the mortality from bowel-complaints falls on the same year. The high means for the even years at Gibraltar, and the odd at Bermuda, may be thought owing to the exceptional years 1828 at the former, and 1819 and 1843 at the latter; but if for the ratio of 121-1 at Gibraltar in 1828, that for 1818, viz., 5-6, be substituted, the average for the even years will be 3-26, as against 1-52 for the odd; and if for 229-4 in 1819, and 121-6 in 1843, at Bermuda, that for 1821, viz., 14-2 x 2 be employed, the average will be 5-31 for the odd years, as against 3É31 for the even one, showing in both cases a decided preponderance of the mortality in the one year over the other, independent of these severe epidemics.

II. The Season at which Mortality occur at each Station.

It is important in this inquiry to determine with accuracy the season at which the mortality occurs at each station; the facts available, however, are often insufficient. In Abstract XXX of Appendix to the Statistical Report on the health of the troops in the West Indies, from 1817 to 1836, the deaths from all causes in each regiment in Jamaica, excluding the artillery, are given for the different months in every year; these in the twenty years amounted to 6,117. Including the artillery the deaths in the twenty years were 6,596, out of a strength of 61,567, or 127- per 1,000. The Medical Returns account for 121-3 per 1,000 only; the difference 6-5, the compilers of the report were of opinion, arose probably at outposts, where the men were attended by civil practitioners, who omitted to report the causes of death, and a few of them from accident or violence too sudden to admit of treatment.* The mortality from fever, shown in the Medical Returns during the period, was 10Г9 per 1,000 of mean strength, so that, as near as may be, fever alone caused fivesixths of the total specified mortality, and if the opinion of the reporters be correct, which is most probable, an equal ratio of that which has not been specified must have arisen from this form of disease. No material error then will be committed if the deaths from all causes, in the line-regiments, be employed to show the progress of fever from month to month in that Island. Taking them, therefore, and adding those for the different months of the ten odd years together, and treating those for the even years in the same manner, the following sums are obtained :—

[table]

These numbers show a minimum in May in the odd year, from which they increase slightly in June, and rapidly through July, to a high maximum iu August, from which the deaths diminish to October, but attain a second maximum in November, from which they decline regularly to the minimum in March in the even year. The deaths continue more numerous in the even year up to June, and go on to October without fluctuating greatly, though with a disposition to a maximum in August as in the odd year ; in November, however, there is a marked increase with a considerable maximum in December, which declines regularly into the lower minimum of May of the odd year. These inflections will be more apparent on examining the following diagram in which the curves of the two periods are given, commencing in March in each, the scale being 1 inch for 200 deaths. The fine lines show the actual mortality, the thicker lines the corrected curves, the data for which are given below. The lines for the even years are dotted to distinguish them from the odd years.

The course of the curve to July in the odd year, and its position for October and November, indicate some disturbing cause in August and Sep

* Statistical Report on Health of Troops in West Indies, p. 44.

.

Though this disease seems commoner all the year round, yet the greatest prevalence is during the months of April, May, and June, coincident with that of fever. After a partial diminution in September, there is a considerable increase again in October.

The admissions and deaths for nine years, from 1838 to 1846 inclusive, for the Mediterranean and American stations, are given in a Report on the sickness among the troops serving there in those years. The deaths in most of the cases are too few to give regular curves, though they indicate generally the sickly months. In all the Mediterranean stations fevers commence to increase in June, are most frequent in July and August, from which they decrease, being nearly as frequent in October as in June. Affections of the bowels get more frequent in May, are pretty numerous in June, from which they gradually rise to October, and afterwards fall rapidly to January. The deaths from these affections do not follow quite the same course as in fevers, but, from their greater duration, are more postponed towards the end of the season, as will be obvious from the following summary, including those for the Ionian Islands, Malta, and Gibraltar :—

[table]

Of the latter class of diseases, 102 were dysentery or diarrhoea, and 39 chiefly peritonitis and enteritis, but they cannot be separated from the others.

Though the season of sickness in the Mediterranean is indicated generally by the above remarks, it may be well to add further information regarding the plague of Malta, and the epidemics of yellow fever at Gibraltar. The last plague at Malta commenced in April, 1813, and the deaths the following months were—

[table]

The disease thus culminated in July, the period when fevers there are most common; but it is probable that the attacks were materially diminished after that by the measures adopted to limit its spread.

On the various occasions in the present century that yellow fever has prevailed at Gibraltar, it has attained its greatest force from the middle to the end of October. Cases have been met with as early as the middle of July, but it was not before the end of August, or beginning of September, that it has begun to spread. From October it has gradually diminished, lingering in the severer outbreaks to the end of December, or even a few cases extending into January.t

In Bermuda, in ordinary years, the greatest number of fevers occur in June, July, and August, from which they diminish slowly through September and October. On the occurrence of yellow fever there, however, August is the month when its greatest force is displayed, though it continues to cause great mortality in September. From this, however, it rapidly declines, though cases are met with in November,]: or even, as on a late occasion, towards the end of December. §

Affections of the stomach and bowels are most frequent from May to August inclusive, during which period they lead to the greatest mortality.

In Nova Scotia and New Brunswick the greatest frequency of fever is from May to September inclusive, and in Canada from June to September. The

* Statistical Report on the Health of Troops in Mediterranean, 1817-36, p. 2S«.
+ Statistical Report on the Health of Troops in Mediterranean, 1817-36, p. 89a.
% Statistical Reports, Bermuda, 1817-36, p. lb, and 1837-16, p. 177.
§ Lancet, January 21, 1865, p. 71.

deaths from fever in the former are too few to present any decided feature when taken month by month. In Canada they are most frequent in August, September, and October. Out of 187 deaths recorded, 78 occurred in those three months. Affections of the stomach and bowels are prevalent from June to October, both in Nova Scotia and Canada. In the former the deaths from these, in the different months, are too few to form any opinion on. In the latter the greatest mortality coincides nearly with their frequency.*

There are unfortunately no records of the prevalence of a mortality from fever and dysentery in Mauritius, in the different months, in the Report on that station.

The Statistical Reports give the sickness among the troops in Cape Town distinct from those on the frontier, up to 1836. Subsequent to this year the sickness for both portions of the station, and Natal, have been included in the same general Return. There is a nominal record of the casualties in the Principal Medical Officer’s office on the station, extending from 1st January, 1826, onwards. From this I have taken the deaths in each month from fever, and from dysentery and diarrhoea, up to 31st December, 1864, a period of 40 years. Keeping those at Cape Town distinct from those at other parts of the station, and arranging them in the odd and even years, and placing the fevers and dysenteric affections for the same years together, they are—

[table]

The numbers for Cape Town are too few to develop the curve of mortality very satisfactorily; and, small as they are, they present several of those disturbances which have been noticed above in commenting on the deaths in Jamaica. For instance, 3 of the 5 deaths in April of the odd years occurred

• Statistical Reports, Canada, 4c, 1837-46, p. 215.

[graphic]

MEDICAL REPORT FOR 1864. 451

in 1827, 2 of the 4 in June in 1825, while 15 of the 34 deaths in the 20 odd years occurred in 1825 and 1827 alone. These show the existences of causes at that time which have since had their influence much reduced, but they prevent any minute analysis of the facts in the Table. It is obvious, however that there is a considerable increase of fever in December of the odd years, which is more highly developed in January of the even year. From this period the mortality remains very low until January of the odd year. The higher numbers of March, April, May, and June, are almost entirely owing to the exceptional cases in 1825 and 1827 ; the remainder is but little different from the even year. It will be observed that coincident with the rise in fever the dysenteric affections became more fatal, and that the loss from these in the first six months of the even year amouuis to 10, while in the corresponding period in the odd year it was 7 only; and the deaths from them in the whole even year exceed those iu the odd. Many of the fatal attacks, which elsewhere might havo taken the form of fever, have here undoubtedly taken tliat of dysentery or diarrhoea; and if allowance be made for the exceptional cases of 1825 and 1827, the excess of mortality would have been found here in the even year, as may be seen by Table I, it was on the frontier stations about the same period.

The details for the frontier stations show 78 fatal cases of fever in the odd years, against 77 in the even; but, of the dysenteric affections, 126 in the former against 171 in the latter. The strength varied from about 300 in the earlier years to above 7,000 in some of the latter; and the wars of 1835-6, 1846-7, and 1851-2, occurred during the period, in the last two of which, owing to the increased strength and greater exposure, the number of deaths was much increased; still it will be seen that August and September, both in the odd and even years, present the least mortality from fever, while iu both January presents the greatest. Combined with the dysenteric affections, December, in both years, shows a distinct increase iu mortality, while in each about four-tenths of the whole mortality for the year occurs in January, February, and March.

III. The Connection of t Waves with Terrestrial Magnetism.

To apply the details wrought out above it is now necessary to examine into the connection of the waves with terrestrial magnetism.

The phenomena of magnetism are usually referred to three elements, viz., first, the deviation of a magnetic needle, moving freely in a horizontal plane, from the meridian, which is called the variation, or declination; second, the deviation of a needle, moving freely in a vertical plane, from the horizontal line, the dip or inclination; and third, the force by which these are produced, which is denominated the magnetic intensity. These elements vary at different

Points on the earth’s surface; but, having been determined at many, these have been marked on maps, and those of similar value joined by lines, constituting the isogonal, isoclinal, or isodynamic lines, respectively. These elements undergo a secular change, varying in rapidity at different places, so that a chart which represented the facts connected with them at a certain epoch, does so sufficiently well for a considerable period, both before and after, yet it becomes sensibly erroneous when it is much prolonged.

On examining these systems of lines, it is found that some of the isogonic curves pass from the southern to the northern hemisphere, across the parallels of latitude, while the course of the others does not agree with the advancing edge of the pandemic waves: they may therefore be set aside for the present. The isodynamic lines coincide with the advancing edge of the waves in some places, but they present too bold a curve to the northward, over the centre of Europe, to indicate the advance of the waves with precision, and elsewhere their accordance is not satisfactory. The isoclinal lines, on the contrary, which encircle the earth at some distance from the magnetic poles, mark out a series of zones, each of which seems to be reached by the advancing wave, at every point in longitude, about the same time, and to be gradually overspread by it in its onward course, leading to outbreaks of disease in that zone, more or loss diffused or intense as the circumstances, whether meteorological, local, social, or personal, are favourable or otherwise.

In the ” Philosophical Transactions” for 1840 there is a chart of the isoclinal

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line by Sabine, embracing the basin of the Atlantic, with the neighbouring portions of Europe and North America, and the west coast of South America. The epoch is 1838. In the second volume of Taylor’s “Scientific Memoirs” there is a chart (PI. xx) of the isoclinal lines for about the same epoch, calculated by Mr. Oauss according to his theory. The lines in the latter correspond very closely with observations over a considerable portion of the globe, but elsewhere deviate from it more or less. In forming the chart attached to this paper, Sabine’s lines have been used so far as they go. They have been continued by adopting Gauss’s chart, correcting their position by the observations accompanying the paper, and others from some other sources. There may be some errors committed, but they will not be to such an extent as materially to affect the objects here sought for.

In the accompanying chart the isoclinal lines for 70° S., 53° and 30° S., 0°, 30″, 53°, 70°, aud 80° N, are inserted. These have been selected as representing, with tolerable accuracy, the position of the advancing edge of a wave on the 1st January each consecutive year. It is possible that, on acquiring more extended information, these positions may require readjustment. If the progress of the wave, from one of these lines to the next, be assumed to be regular, the approximate date of its reaching any station between them can be ascertained by direct measurement on the chart, or it may be deduced from the observed dip at the place. This, as will be found hereafter, is an important point, and” it is in the main correct, though it may be somewhat interfered with by those rapid changes in the terrestrial magnetism which take place about the period of the summer solstice in either hemisphere, and the equinoxes.

It is stated above that the magnetic elements undergo a secular change. As regards the dip, the change is, in general terms, as if the isoclinal lines moved gradually to the westward, maintaining their relative position to the parallels of latitude. When their direction is nearly the same, there is little alteration of the dip for many years; but where they are oblique it is much more rapid. London and the Cape present two instances of the latter, where the change is very great, and which may be referred to here, to show how far the adoption of the lines in the chart will apply to the purposes intended in this paper, even in these extreme cases. Graham found the dip at London, in 1723, to be 74° 10′, and Sabine in

1820 70° 8′

1810 69° 12′

1860 68° 20′

Taking the position of the advancing edge of a pandemic wave on the 1st January to be 70° N., the dates on which it would have reached London at these different periods would have been

1723 June l.

1820 January 1.

1840 December 15.

1860 November 16.

At the Cape of Good Hope the dip was found to be, in

1792 47° 25′

1818 50* 47′

1836 52° 35′

1851 64* 2′

And assuming the edge of the advancing wave to reach 53° S. on 1st January, it would be at Cape Town at each date respectively on April 10, February 10, January 7, and December 18.

So that while at London the date of the arrival of the wave is receding into the previous year with the diminishing dip, at the Cape, in the opposite hemisphere, the same thing is taking place as it increases.

A wave with a two-yearly period, starting from one of these lines at the commencement of, say, the odd year, will be at the next to the northward at the beginning of the even year; and so on, the first part of the wave being met with in the alternate zones in the odd years, and in the intermediate ones in the even. It will be found in each zone too, always in an odd or always in

[FIGURE MAP]

MEDICAL BEPORT FOR 1864. 463

an even year. The following may be given as the position of the first part of the waves on the 1st January in the respective years :—

Odd Years. Even Years.

70° S. 53′ S.

30° 0′

30″ N. 53° N.

70° 80° N.

Sierra Leone is situated in the zone commencing at 30° N,; fevers there present their maximum in the odd years. Jamaica is in the same zone, and gives a similar result. Malta and Gibraltar are in the zone commencing at 63° N.; the excess of fevers at these is in the even years. Nova Scotia and Canada are in the zone commencing at 70° N. ; fevers at these present their maximum iu the odd years.

There are several stations so situated in their respective zones that the wave does not reach them until a period of the year when the local causes of disease are comparatively quiescent. In such the outbreak does not commence until the season when these regain their activity, which frequently carries it on into the following year. Ceylon affords an instance of this. The wave would reach Colombo about 1st November, Trincomalee about 1st December, in the odd year. By referring to the Table showing the deaths from fever at these stations in the different months, it will be seen that the mortality is nearly at a minimum in those months. At Colombo it increases in January, but does not reach its full amount until April ; while at Trincomalee April and May are the sickliest months. Table I shows that the mortality from fevers in the even years in Ceylon is 30-49 per 1,000, while that in the odd is 16-27 only, clearly showing that the wave does not exercise its full influence until combined with activity of the ordinary local causes of disease. From this circumstance arises the apparent anomaly of a station, like Ceylon, placed in a zone which the wave occupies in the odd years, having its excess of mortality in the even years: but the explanation, it will be seen, is quite reasonable.

Mauritius, and the Cape Frontier and Natal, are in a similar position. The first part of the wave would reach these stations about the beginning of December of the odd year. The greatest mortality from fever and dysentery has been shown above to occur in the three first months of the even year on the Cape Frontier; and though there be no facts given, analogy indicates the period following the summer solstice as the season of greatest sickness from these diseases in Mauritius also, and consequently the mortality from each is highest in the even years. Cape Town, up to 1836, the latest year in Table I, was within the zone commencing at 53° S., and should have shown the highest mortality from fever in the even years, on the principles here set forth. Combined with dysentery and diarrhoea, the mortality in both years is about equal; and but for the disturbing causes previously noticed, it is probable that that in the even years would have had a decided preponderance.

Bermuda affords a further illustration of the principle under consideration. That station is so situated in the zone commencing at 53° N., that the wave should reach it about the middle of October of the even year. It has been shown above that, on ordinary occasions, fevers culminate in August, after which they decline. During epidemics of yellow fever, most deaths have occurred in August and September; they are reduced greatly in October, and nearly disappear after November. The wave then reaches the station after the greatest force of the local causes has passed, and their activity is greatly reduced; and, as at Ceylon, Mauritius, and Cape Frontier, the epidemic outbreak should be expected iu the following, in this case the odd year. Accordingly it is found that the greater mortality from fevers occur in the odd years, even if that from the same epidemics of 1819 and 1843 be omitted, while the most severe epidemics have occurred in the odd years, such as those of 1819. 1843, and 1853. In October, 1837, there was a slight epidemic, but confined to one island, and to persons communicating with it.* There have been others, however, in even years, though, so far as the information within my reach goes, of a less general or violent character than during the odd. In 1796 yellow fever broke out at Ireland Island, one of the group, but it was seven months, or

* Milroy in British and Foreign Mcdico-Chirurgical Review, vol. xxxiii, p. 182.

in the following year, that it reached St. George’s, the chief one. In 1818 this disease appeared again at Ireland Island, but did not break out at St. George’s before August of the following year.* Again there were outbreaks in 1812, 1856, and 1864, the last of which seems the only serious one, and to have developed its full force chiefly on persons recently arrived in the locality from colder countries, and who are less acclimatized than those longer resident, t I have no information as to the time the disease appeared in 1812, or 1856; in 1796 and 1818 it must have been late in the year, which would have brought it within the operation of the first part of the wave. In 18G4 there appears to have been fatal cases at St. George’s in June, and early in July.J It is therefore most likely that this epidemic arose under the latter part of the wave which reached these islands in October, 1862, local circumstances being favourable, as explained above in connection with Jamaica.

There are two exceptions to these principles, doubtless owing to some disturbing cause which I have not been able to detect as yet. These are in the West India Command and the Ionian Islands. The former, situated in the same zone as Sierra Leone to the east, and Jamaica on the west, presents a slightly smaller death-rate from fever in the odd years than in the even. On the other hand, the deaths from dysenteric affections are somewhat greater in the odd years than in the even. The sums of the deaths from both causes are in the odd years 56’41 per 1,000, and in the even 56’27, results which may be considered identical. Single stations of the group, however, show numerous outbreaks in the odd years, corresponding with those at Sierra Leone or Jamaica.

The Ionian Islands are clearly in the same zone with Malta and Gibraltar; and the wave reaches Corfu, the northernmost, about the beginning of February of the even year, early enough to permit of the full effect being developed that year, as at the other Mediterranean stations: yet the excess of mortality from fevers, and from dysenteric affections, between 1817 and 1846, both fell in the odd years. Here, however, as in the West Indies, single stations occasionally display a high rate of mortality in the even year, corresponding with that at Malta or Gibraltar, though, from the small force at them, the actual number of deaths may influence the total for the Command to a slight extent only.

IV. The Influence of the Waves in exciting Epidemics.

The influence of these waves in causing outbreaks of disease is manifest in two ways, viz., first, under the operation of the same wave in the same year, at points often very different in latitude, and embracing in longitude, it may be, almost half the circumference of the earth; and, second, in successive years at points more and more to the northward, as the waves pursue their usual course. To illustrate these it is necessary to examine the records of disease at a sufficient number of distinct and widely-spread stations for a series of years, when it will be found that many epidemics, which have hitherto been thought independent of each other, were merely local manifestations of the same general influence, and others which were considered accidental, aud to account for which much labour has been expended and ingenuity displayed, fall into these places naturally, as subordinate to the general law.

The investigation may be commenced with the Pali plague, which broke out at Cutch and Guzerat in Hindustan in 1815. ‘As will be seen in the chart, Cutch and Guzerat are situated close to the south of the isoclinal of 30° N., at which, according to the Table given above, the advancing edge of the wave would be found on the 1st January of the odd year. In the course of 1815 the disease broke out in these districts, and caused great mortality. At Sierra Leone, which is in the same zone, there were, according to Dr. Barry, a number of cases of yellow fever this year. At Jamaica, also in the same zone, the mortality among the troops rose to 120 in the thousand, from 94 the previous year. Though the diseases causing this are not specified, it is highly probable, from what has already been said with regard to Jamaica, that fever was the chief. I have no evidence as to the progress of diseases in Egypt or Syria this year. In 1816, when the wave would overspread the Mediterranean north of

• Statistical Report«, 1817-36, Bermuda, p. lb.

t Lancet, October 8,1864, p. 421. % Ibid.

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MEDICAL REPORT FOR 1864. 455

Malta, and much of Europe, the records of sickness among the troops in the former, on which the Statistical Reports are based, had not commenced; but Henuen, in his ” Medical Topography,” gives some details with regard to the Ionian Islands, from which it appears that, while in the latter half of 1816 the mortality among them was small, in 1816 it increased very greatly, chiefly from fever, which then produced a death-rate of 36-5 per 1,000. Typhus became very prevalent in Italy; and plague, which had for some years previously been common in Albania, spread from Bosnia to Sclavonia and Croatia, besides presenting a number of local outbreaks in Albania itself, as at Arta and Previso; and a minor one at Comitato, a mountain village in Cephalonia. In this island the mortality from remittent fever among the troops, the same year, amounted to the very high ratio of 197 per 1,000; and that among the inhabitants, from the same disease, was unusually great. In the winter 1816-17 a malignant fever, of the nature of typhus apparently, was very prevalent at Algiers. In 1817, the advancing edge of the wave having reached the isoclinal of 70° N., it would in that year overspread Northern Europe, the British Islands, and the American Continent from Cape Hatteras to the isoclinal of 80° N. In this year a very severe epidemic of fever was experienced in Ireland and Scotland, embracing, according to Murchison, both typhus and relapsing fever; while at Newcastle there was an outbreak of pythogenic fever. Cases of relapsing fever had shown themselves, in the end of 1816, in the south of Ireland; but the disease did not become general until 1817. In Nova Scotia and Canada the mortality among the troops, from fever, was 1.8 and 3.2 per 1,000 respectively, declining to 0-0 and P8 the following year. The fever in Ireland was accompanied by much dysentery; and iu Nova Scotia and Canada the mortality from dysentery and diarrhoea, among the troops, was 4-9 and 39 per 1,000 respectively—ratios much higher than any subsequent year in Table II, with one exception.

These facts indicate with precision the regular advance of the wave from the isoclinal of 30° to that of 70° N., and beyond it, over 150° of longitude. As the wave has a two-yearly period, the sickness of the first year is often more or less continued into the second, or other outbreaks may take place at points which had previously escaped, as explained above. Accordingly in 181fi a severe epidemic of remittent fevers, with yellowness of skin, prevailed in the valley of the Ganges from Dinapore to Delhi. The fever of 1816, in Italy, continued into 1817. This year also there was a severe epidemic of yellow fever at New Orleans, Natchez on the Mississippi, and Charleston, and among the troops in the Bahamas Islands. In 1818 there were two cases of yellow fever in Philadelphia, according to La Roche.

The wave next following that just examined, can be traced from the Cape of Good Hope. From old Returns available here, the mortality from fever among the troops at Cape Town, in 1813, was 0.2 per 1,000, and in 1814 it rose to 0.9. This station was then slightly to the north of the isoclinal 63° S., and consequently experienced the advancing wave early in the even year. The next indication is at Ascension, which being just to the north of the isoclinal 0°, also comes under the first part of the wave in the same year. Here, according to the Returns given by Burnett in his account of the fever in the Bann, there were four admissions from fever in 1816, against two only the following year. The numbers are small, it is true, but, so far as they go, they indicate the operation of the general influence. In May, 1817, Copland mentions having met with several cases of yellow fever among seamen at Sierra Leone,* the next zone to the northward of that including Ascension. This year also the mortality among the troops, from all causes, in the West India Islands, which in 1816 had amounted to 151 per 1,000, increased to 162-1, of which 59.4 was from fever, and 65.4 from bowel complaints. In Jamaica there was rather less mortality than in 1816- The Pali plague in Cutch and Guzerat seems to have been more prevalent in 1817 than in the previous year. In 1818 the wave is to be looked for to the north of the isoclinal of 53° N., and its operation is indicated by a mortality from fever at Malta of 5.6 per 1,000, three and a half times greater than the previous year, At Gibraltar the ratio was 5.8 per 1,000, which, though from want of Returns for 1817 cannot be compared with it, is

* Dictionary, art. “Pestilence HcemagMtric,” § 143.

higher than in any other year in Table II, except 1828. One case at this station, this year, was returned as yellow fever. In the Ionian Islands the death-rate was lower than in 1817. Petechial fever continued rife in Northern Italy in 1818, and plague ravaged Morocco. Bermuda, which is in the northern part of the same zone as those countries, showed a high death-rate from fever this year, when the yellow fever appeared at Ireland Island late in the season, and the following year became developed into a desolating epidemic. In 1819, the wave passing the isoclinal of 70″ N., there was a death-rate of 2.9 per 1,000 among the troops in Nova Scotia, while that of the previous year in Canada was maintained. Yellow fever appeared epidemically also in Baltimore, Philadelphia, New York, and Boston. Typhus and relapsing fever continued in Ireland and Scotland, though the epidemic force was much reduced. In this year too, bilious fever prevailed in Iceland, but there is not sufficient information regarding the season at which it appeared to admit of its being referred to this or the preceding wave.

As with the previous wave, various epidemics were experienced in the second year of that under consideration. In the Mediterranean, plague was severe at Constantinople in 1819. The mortality from fever was higher among the troops in the Ionian Islands than in- 1818, though less in Malta and Gibraltar; and yellow fever, an isolated case of which was seen at the latter the previous year, had become developed to the dimensions of an epidemic at Cadiz, Xeres, Malaga, and other places in the south of Spain. The severe epidemic at Bermuda in 1819 was accompanied by similar outbreaks at New Orleans, Natchez, Mobile, Charleston, and the Bahamas.

The wave next in order would have been experienced at the Cape of Good Hope in 1816, but there are no returns for that year available. Its first indications are met with in Ceylon in 1818, where the mortality from remittent fever, chiefly among the troops, rose to 133.8 and that from dysentery and diarrhoea to 55.5 per 1,000—the former about four and a half times the previous year’s ratio, and the latter two and a half times more. Ascension, as stated above, experiences the advancing wave in the early part of the even year; and fever occurs in the same year as at Ceylon. In 1818 the admissions from this disease there were 12, or six times more than in 1817, and embracing nearly every man on the island; and one death occurred, the symptoms, according to Burnett, being those of yellow fever. St. Helena is to the south-east of Ascension, so situated in the zone, between the isoclinals 30° S. and 0°, that the wave would reach it about 1 st June of the odd year, later in the season than the usual period for sickness in the southern hemisphere; consequently, on the principles already announced, fevers there should be looked for then in the next warm season. There were no returns of the sickness among the troops at this station in 1817; but in 1818 the deaths from fever amounted to 6.0 in the 1,000, being more than four times the ratio of 1819. In the latter year one case was returned as yellow fever. At Lima, in Peru, a large body of Spanish troops from Europe was assembled, among whom a severe epidemic of fever, supposed to have been yellow, broke out in February, 1818.» Lima, like Ceylon and St. Helena, lies in the zone to the south of the isoclinal 0°, and would be reached by the advancing edge of the wave about 1st November of the odd year, though, ás the active period of the local causes commences about January, fever due to their influence would not assume the epidemic form before that month in the even one. The disease was not confined to Lima, but was met with as far south as lea, in lat. 14° S. In 18)9, this wave, extending from Ceylon to Peru, would overspread the next zone to the north. Accordingly a terrible epidemic occurred in Jamaica; and though the total mortality from fever in the West India Command was less than in -1818, yet at several of the stations it was high; and at Demerara, where the form of fever for years previously had been the ordinary remittent, yellow fever appeared and proved very fatal. In 1819, also, Pali plague was very severe in Cutch and Guzerat; and true plague was epidemic at Susa in the south part of the Mediterranean. In 1820, with the next zone to the north, the mortality from fever in the Ionian Islands was very low; but at Malta the ratio remained pretty high, while at Gibraltar it increased; and in

• Smith, British and Foreign Mcdico-Chirurgical Review, vol. xxxv, p. 210.

MEDICAL REPORT FOR 1864. 4û7

the neighbouring parts of Andalusia yellow fever prevailed epidemically, and typhus was severe in the convict hulks [hulls/bulks] at Toulon. Bermuda was low, but at New Orleans the millesimal ratio of deaths from yellow fever was nearly аз great as the previous year. The wave would reach New Orleans about the middle of May, while the period for the occurrence of yellow fever there commences in July, hence the epidemic of this year must be attributed to the wave under consideration. In 1821 the mortality at Bermuda was high. There was no death from fever among the troops in Nova Scotia, but in Canadá the ratio was 2-8 per 1,000, as against 0-6 in 1820; and at Norfolk, Virginia, and Baltimore yellow fever showed itself. In 1820 and 1821, croup and catarrhal fever were prevalent in Iceland. In 1821, the second year of the wave in the western part of the Mediterranean, there was a severe epidemic of yellow fever at Barcelona, while it continued at other points; and fever among the troops in the Ionian Islands caused a high mortality. In like manner, in 1822, yellow fever was seen at New York ; and at Halifax the millesimal ratio of the deaths among the troops was 19.

The next wave to be considered would be experienced at Mauritius and the Cape in 1818. At Mauritius there was a mortality from fever of 1.1 per 1,000; but from dysentery and diarrhoea of 107, as against Vi and 7.9 respectively the following year. At Cape Town there was no death from fever in 1818, and only a ratio of 1.0 from bowel complaints, but 2.5 and 1.7 respectively in 1819. In 1820, when this wave would be experienced in Ceylon, fever and bowel complaints were comparatively low. At St. Helena, however, the former were nearly twice as numerous as in the previous year, while one case was returned as yellow fever, and the following year there was another. In 1821 the Pali plague was still prevailing in Cutch and Guzerat. The deaths from fever, both in the West India Command and Jamaica, were very high, though less in each than in 1820, but those from dysentery and diarrhoea were augmented. The followiug year, however, the mortality from fever in Jamaica was very high, due in some degree to the arrival of fresh troops from Europe, as previously mentioned. In 1822, the wave proceeding from 53° N, the mortality at Malta was 6-2 per 1,000. At Gibraltar and the Ionian Islands it was less than in the previous year, but at the former one case was designated yellow fever, and this form of disease continued at Barcelona. At New Orleans there was an epidemic of yellow fever experienced, which caused a higher death-rate than that of 1817. In Bermuda the rate among the troops was low in 1822, but in 1823 again high, while both Nova Scotia and Canada, in the latter year, had high death-rates. In London, Cork, and Dublin also, in 1823, fever became more freaueut, as indicated by the admissions to the fever hospitals in these places; and the following year they increased considerably in London and Dublin, and also in Edinburgh and Glasgow.

In 1820, at Mauritius, there were indications of the next wave, which, like that of 1818, produced a mortality from fever of 0-7 per l,000 only, rather less than that of the preceding year, but one from dysentery and diarrha-a of 12 9 higher than that of 1818 or 1819. At Cape Town the ratio of 25 from fever continued, and that from bowel affections was also much the same. In 1821, as will be seen by Table II, the aggregate mortality from these classes of disease was considerably diminished at both station*. In 1822, when this wave would be experienced at Ceylon, there was a large increase of mortality from fever there, and that from affections of the bowels also increased materially. The returns for St. Helena were nut available for this year. At Ascension, from 26th November, 1821, to 7th May, 1823, three cases only of fever came under treatment. In 1823 the wave entered the zone commencing at the isoclinal of 30″ N., and yellow fever appeared at Sierra Leone as a very severe epidemic; and at least one case of this form of the disease seems to have

proved fatal to a European at Bathurst on the Gambia.* Both in the West ndia Command and Jamaica, fever and bowel complaints were comparatively low in 1823; but fever caused considerable mortality among the few white troops at Belize. In 1823, also, yellow fever broke out at Ascension on 11th

• This information I received from an omVrr of the Commissariat, who was at Bathurst at the time, and who stated distinctly that the patient was yellow, and had black vomit previous to death.

May, 18 days after the arrival of the “Baun” from Sierra Leone, with the disease on board, and cut off 21 out of 52 persons residing on the island. The disease appeared on this occasion at the same season as it had done in 1818, and after some rain hnd fallen. In 1824 the wave would proceed from the isoclinal of 53° N. The ratio of mortality from fever in the Ionian Islands remained as high as in the previous year, while those for Gibraltar and Malta, and those for dysentery and diarrhoea at these stations, were very much augmented. Plague became epidemic at Cairo in 1824, and carried off 30,000 persons. Cairo is in the zone between the isoclinal 30° and 53° N., and would be reached by the wave about 1st June in the odd year ; but, as is well known, plague commences in Egypt in December, and loses its epidemic form in June; and by St. John’s day, the 21st of that month, is usually considered to have ceased. In conformity with what has been shown above to be the course of disease in places similarly situated, the epidemic outbreak of plague could not be expected at Cairo before the next sickly period, which would throw it into the following or even year, as in this instance. Plague was also in the Morea in 1824. There was a severe epidemic in the district of Dulcigno on the Montenegro coast. It was also prevalent at Constantinople and Erzeroum. At Bermuda the ratio of deaths from fever remained as high as in 1823, and that from dysentery and diarrhoea quadrupled the previous year’s rate. At the Bahamas, where the troops had suffered very severely in 1823, the loss from fever this year was still high. At New Orleans there was a slight epidemic of yellow fever, and the disease was met with also at Charleston. In 1825 the wave would pass the isoclinal of 70° N. ; and this year the millesimal ratio of mortality from fever at Nova Scotia rose from 0.5 in the previous one to 1.8, and in Canada from 2.3 to 4.3, and the ratios of deaths from bowel affections were 0.9 and 0.7 respectively, against none in 1824. The admissions into the fever hospitals in London, Cork, Edinburgh, and Glasgow, all showed a considerable increase in 1825. Dysentery was also prevalent in some parts of Ireland and of France, as it had been the previous year in the Mediterranean and Bermuda, and was this one in Nova Scotia and Canada. As already noticed, sometimes epidemics appeared in various places in the second year of the wave: thus in Lower Egypt, in 1825, plague was rife; and at New Orleans there was a death-rate from yellow fever nearly equal to that in 1824. There was also an epidemic at Natchez. Hennen reported a case of yellow fever in Gibraltar in 1825* In 182C, fever, chiefly relapsing and typhus, increased in Great Britain and Ireland, especially in the latter. Graves, in his “Clinical Lectures” indeed, noticed that many cases resembled yellow fever in presenting yellowness of skin and black vomit. This year also remittent fever was very prevalent in Holland, along the coast of the North Sea, with yellowness of surface. At Norfolk in Virginia there was an epidemic of yellow fever, and at Philadelphia a few cases.

The wave following that just described was observed at the Cape in 1822. At Cape Town the millesimal ratio of deaths from fever was 2.5, as against 0.0 the previous year, and that from dysentery and diarrhoea 6.5, against 2.5 in 1821. On the Cape Frontier, the returns for which are available this year for the first time, the ratio from fever was 4.8, and from bowel affections 3.2. The following year there were 17 and 00 respectively. At Mauritius there was no death from fever in 1822; and though bowel complaints caused considerable mortality, the ratio was less than in 1821, and very little higher than in 1823. In 1824 the wave would have reached the isoclinal 0°; and in Ceylon the ratio per 1,000 of mortality from fever was five times higher than in the previous year, and that from dysentery and diarrhoea more than doubled. The first Burmese war commenced this year ; and the troops in the field, in various parts of that territory, suffered very severely from fever and dysentery. That form of fever called “dengen” appeared in the Burmese expedition, and at the same time there were cases in Calcutta. The Ashantee war was then going on in the vicinity of Cape Coast Castle, which, as will be seen in the chart, is in the same zone as the Burmese territory; and here also there was excessive mortality from fever and dysentery. Some of the men-of-war employed on the stations sent part of their crews on shore for some time at Cape Coast, who

• Medical Topography, p. 119,

MEDICAL REPORT FOR 1864. 459

suffered from fever and dysentery. In a fatal case of fever in Huis yictotj coffee-ground fluid was found in the stomach. The exact date is not given, nor the ship’s position at the time, but it seems probable she was in this neighbourhood, and the case occurred between June, 1824, and 1st March, 1825. In 1825 the wave reached the isoclinal 60° N. The fever continued among the troops in Burtnah, aud the dengen spread along the valley of the Ganges for some distance. This year a considerable force of white troops were sent to Sierra Leone aud the Gambia, among whom there was immense mortality from remittent fever. In the West India Command the millesimal ratio of deaths from fever was slightly lower than the preceding year, though that from dysentery and diarrhoea was doubled; but in Jamaica there was a very severe epidemic of fever, also with an increase of mortality from bowel complaints. In 1826 the mortality at Sierra Leone continued unabated. In the West India Command it was somewhat less, though greatly reduced in Jamaica, but there was a high death-rate at Belize. The wave would enter the zone to the north of the isoclinal 53° N. in 1826. In the Ionian Islands the death-rate from fever increased considerably. At Malta it remained the same; but at Gibraltar there was an increase, though with a considerable diminution of that from bowel complaints. Hennen reports several cases of yellow fever there this year.* Plague was prevalent at Constantinople. The ratio of deaths from fever was 1.6 only at Bermuda. There was no yellow fever at New Orleans, but a high mortality from it among the troops in the Bahamas. In 1827 the ratio at Bermuda rose to 4.5, and there was a slight outbreak of yellow fever at New Orleans and Charleston. In 1827 the wave would proceed from the isoclinal 70° N. The ratio per 1,000 of deaths from fever at Nova Scotia rose to 27 from 0.9 in 1826, and in Canada to 4.6 from 3.2. The admissions into the Fever Hospital in London were slightly increased over 1826, and those in Glasgow aud Edinburgh a good deal. In Cork they were quite as numerous as in 1826, but less so in Dublin. In the marshy districts in the south of England, this year, fevers often assumed a remittent form, and were of a violent unmanageable nature, like those in the tropics. In 1828 typhus fever prevailed in Ireland, and continued into the following year. The fever in Ireland had decreased considerably in 1828, but the admissions at Glasgow and Edinburgh were more numerous than in 1827. In this year, the second of the wave in that locality, the plague broke out at Odessa.

The next wave to be traced is that starting from the isoclinal 53° S. in 1824. At Mauritius, this year, the ratio of deaths from fever remained the same as the preceding one; but there was a considerable increase in that for dysentery and diarrhoea, which diminished a half next year. On the Cape Frontier there was no death from fever, but a ratio of 2.l from bowel complaints, which increased to 8.6 in 1825. At Cape Town the deaths from fever doubled in 1824, while those from bowel complaints diminished, but the following year both increased very much. In 1826 the wave would be in operation in the zone commencing at the isoclinal 0°. That year fever in Ceylon was slight, though bowel complaints were pretty numerous, and the deathrate from them considerable; the following year both were increased. In 1826 there was a death-rate of 2.2 per 1,000 from fever among the civil population in St. Helena, which was nearly equal to that of three subsequent years, consequently very high. This rate, however, was continued into 1827. There is no information regarding Ascension this year, aud the men-of-war on the coast of Africa seem to have had very little sickness. In 1827 the wave would pass the isoclinal 30° N. At Sierra Leone this year the mortality among the troops from fever was not quite one-sixth of what it had been in the two preceding years, though still very high. In the West India Command fever proved nearly twice as fatal as in 1826, and in Jamaica a very severe epidemic occurred. At Belize there was also a high death-rate. The dengen or dandyfever, and yellow fever, appeared at St. Thomas in the West Indies in 1827, and affected a number of the other islands as well. In 1828 the wave would proceed into the zone beyond the isoclinal 53° N. Fever, which in 1827 was high in the Ionian Islands, was this year considerably higher, and the mortality

* Medical Topographv, p. 119.

from affections of the bowels was also greater. In Santa Mama, one of these islands, the millesimal ratio of deaths from fever alone was 1497. In Malta the ratios from both fever and bowel complaints were higher than in 1827, and at Gibraltar there was a very severe epidemic of yellow fever. During these occurrences in the military stations in the Mediterranean, the neighbouring countries displayed much febrile disease. Plague raged iu Egypt, Syria, Greece, at Constantinople, in the Russian army in the Danubian provinces, at Bucharest, and Cronstadt in Transylvania. Petechial typhus was epidemic at Naples. At the Bahamas there was considerable mortality among the troops. At New Orleans a slight epidemic of yellow fever. The dengen was prevalent this year at New Orleans, and at the towns in the Southern States of America. In 1829 the plague continued in Egypt, Greece, and Syria; and was experienced at Odessa. In the west, yellow fever prevailed extensively at New Orleans. The wave would occupy the zone beyond the isoclinal 70° N. in 1829. Fever at this time seems to have been declining all over the British Islands. In Nova Scotia the millesimal ratio of deaths rose to 2.6 from 0.5 the previous year; in Canada it was less by half.

The wave following that last described would be at the isoclinal 53° S. at the beginning of 1827. This year, at Mauritius, the millesimal ratios of deaths from fever, and dysentery and diarrhoea, were 30 and 67 respectively, both showing considerable advances on those for the previous year. On the Cape Frontier there was a considerable ratio from fever, though none from affections of the bowels. In Cape Town the ratio of deaths from fever was low this year. In 1827, however, it increased very much, when those on the frontier and at Mauritius had fallen. In 1828, when Ceylon would be under the influence of this wave, there was less mortality there from fever and bowel complaints than in the previous year. The returns are not available for St. Helena this year. An attempt was made at this time to form a settlement at Fernando Po, which, as will be seen by the chart, lies close to the isoclinal 0°, in the Bight of Biafra on the coast of Africa. Out of 25 marines landed here in 1827, all, except one, had fever in the course of the following year, and eight died.* Of 30 mechanics who arrived in November, 1827, all had suffered. There was no record of the deaths. A few were invalided, and five only remained in June, 1828.t In 1829 the wave would pass the isoclinal of 30° N.; and this year there was a severe outbreak of yellow fever at Sierra Leone, and the same form of disease prevailed in several of the men-of-war on the coast of Africa, and was experienced this year also at Fernando Po, among the marines and mechanics who arrived in June, and among the vessels engaged in the palmoil trade in the rivers on the opposite coast.t As had occurred in 1823, when yellow fever was prevailing at Sierra Leone last, the mortality from fever this year was small, comparatively speaking, both in the West India Command and Jamaica. In 1830 yellow fever seems to have been epidemic at Goree and St. Louis on the Senegal. The advancing wave would cross the isoclinal 53° N. in 1830, and in the Ionian Islands fever caused about the same mortality as the previous year, while that from bowel complaints was less. At Malta the ratios from both fevers and bowel complaints were much increased; at Gibraltar there was a slight increase in both. Plague prevailed this year along the course of the Euphrates, from Bassorah to Aleppo, and in Egypt and Syria. Petechial typhus was common in Maples, and severe typhus in the convict hulks at Toulon. In the western hemisphere there was a slight epidemic of yellow fever at New Orleans ; while in both the West India Command and Jamaica, as in 1824, the mortality from fever was considerably increased. The wave would pass into the zone beyond the isoclinal 70° N. in 1831 ; and at Nova Scotia trie millesimal ratio of deathe from fever rose to 6.5 from 0.4 in 1830. In Canada it remained, the same, but increased the following year. In 1831 typhus became very prevalent in London, Glasgow, and Edinburgh; and the number of admissions into the fever hospitals in Cork and Dublin was

* Bryson. Climate and Diseases of African Stations, pp. 60, 61. t Ibid. pp. 69, 70.

X Bryson, Account of Origin, Spread, and Nature of Epidemic Fever of Sierra Leone, p. 60.

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MEDICAL REPORT FOR 1864. 461

increased. The disease seemed less in London in 1832 ; but in Ireland, and still more in Scotland, the attacks were more numerous, as in Canada.

The next wave in succession would pass the isoclinal 53° S. in the beginning of 1828. At Mauritius this year the millesimal ratio of mortality from fever reached 73, and that from affections of the bowels 177. On the Cape Frontier these were 5.6 from each class, and at Cape Town 5.2 from fevers, with none from the dysenteric affections. In 1830 the wave would pass the isoclinal 0°. In Ceylon this year there was little increase of mortality from fever over the preceding year, and that from affections of the bowels was slightly diminished. At Fernando Po the fever met with at the end of 1829 was of a milder type than in the earlier part of the year, and seldom proved fatal. In the summer of 1830, however, it resumed its work of destruction in a more malignant form. The greatest mortality occurred in a party which arrived from St. Helena in April. It consisted of men, women, and children, amounting in all to fourteen, of whom there were only two remaining alive by the end of July.* In 1831, when the wave would pass into the next zone, there is no account from Sierra Leone. The mortality from fevers and affections of the bowels in the West India Command was somewhat higher than the previous year, and in Jamaica there was a severe epidemic of the former. In 1832 the wave would proceed beyond the isoclinal 53° N. The mortality at all the Mediterranean stations from fevers diminished from the previous year, and in the Ionian Islands only was there an increase of that from affections of the bowels. At New Orleans there was a moderate outbreak of yellow fever, which the following year, however, became developed into a severe one. There was a severe epidemic of plague at Bassorah, Bagdad, and Mecca, this year. The wave would pass the isoclinal 70° N. in 1833. In Nova Scotia and Canada fever produced little mortality this year, but in 1834 the ratios increased in both. In Vancouver’s Island, on the west coast of America, intermittent and remittent fevers were unusually prevalent in 1833, owing, it was supposed at the time, to the extensive breaking up of laud for agricultural purposes. The island, it will be seen, is in the same zone as Canada, and would be under the influence of the same wave. The admissions into the fever hospitals in London, Cork, Dublin, Glasgow, and Edinburgh, were all diminished in 1833, though in 1834 the numbers increased a little at all except Edinburgh. The latter year fevers seem to have been common in Ireland, extending into 1835.

The next wave to be investigated would be at the isoclinal 53° S. on 1st January, 1830. At Mauritius the ratio of deaths from fever increased, though that yeat dysenteric affections diminished. On the Cape Frontier there was a ratio of Г7 from fever, against 00 in 1829, and at Cape Town of 0.9 against 00. The latter increased in 1831 to Г7, with a similar ratio from dysentery and diarrhoea. In 1832, when the wave would pass beyond the isoclinal 05, there was a considerable increase of deaths from fever and bowel complaints at Ceylon. In 1833 there was a very severe remittent prevailing at Calcutta. In the West India Command fever caused a slightly increased mortality over the previous year. At Jamaica it had gone on diminishing from 1831, though still amounting to 61.1 per 1,000. In 1834 the wave would extend into the zone beyond the isoclinal 53 N. This year there was a slight increase of mortality from fever in the Ionian Islands, but a diminution in that from affections of the bowels. At Malta the deaths from fever were more than trebled, and those from dysentery, &c, doubled, while at Gibraltar the ratios from both were materially increased. Plague prevailed in 1834 at Alexandria, Tripoli, and Constantinople, and a fever denominated ” pernicious” at Athens, which continued into the following year, as the plague also did in Lower Egypt in a very severe form. In 1834 there was a low ratio from yellow fever at New Orleans, and from fever generally at Bermuda. In 1835 the wave would pass into the next zone beyond 70° N. The deaths from fever were less in Nova Scotia this year, but in Canada maintained the previous rate, and typhus was prevalent at Philadelphia. In the British Islands there was an increase in the admissions in the Fever Hospitals in Cork, Dublin, and Edin

* Brj-son, Account of Origin, Spread, and Nature of Epidemic Fever of Sierra Leone, p. 49.

burgh, which was augmented still more the following year in Cork, Dublin, and Glasgow. The Cavalry and Infantry on the home station showed a considerable increase of mortality from fever in 1835, which was increased the following year in the Foot Guards and Infantry, though the ratio of the Cavalry was rather less. In 1836 typhus was prevalent in Ireland.

Another wave would leave the isoclinal 53 S. early in 1832. At Mauritius the ratio of deaths from fever was 1.6, against 0.0 in 1831, but that from dysenteric affections was less. There was no death from fever on the Cape Frontier. At Cape Town the ratio from fever was about half that of the previous year, but that from dysentery and diarrhoea was doubled. In 1834, when this wave would pass the isoclinal 0°, the mortality from fever and bowel complaints was low at Ceylon, though the following year they were both augmented. In 1835, when the wave would pass the isoclinal 30° N., there does not appear to have been much fever at Sierra Leone ; but one case of yellow fever occurred, which terminated fatally with black vomit on 4th September. There was a considerable increase in the ratio of deaths from fever in the West India Command, though in Jamaica it was slightly lower. In 1836, with the wave advancing beyond 53° N., the deaths in the Ionian Islands remained low for that station. In Malta both fever and bowel complaints caused considerably increased mortality. At Gibraltar the deaths from fever increased, but those from bowel affections were less. There was a severe epidemic of plague this year at Constantinople. It was also experienced in Bulgaria. Sophia lost one-third of its inhabitants, and Schumla was affected; and it prevailed at Galatz, Ibraila, Silistria, Bucharest, and along the Danube, this and the following year. Salónica had a few sporadic cases in 1836, but in 1837 a violent outbreak. The disease was also at Smyrna in 1836 and 1837; and the latter year throughout Asia Minor, Syria, Lower Egypt, and coast of Barbary. The millesimal ratio of deaths from fever in the Ionian Islands rose to 12’1 in 1837, almost four times that of 1836. The Pali plague reappeared in Marwar in 1836; and fever with yellowness of skin was very prevalent among prisoners in gaols, and the poorer classes in the native villages, in the Upper Doab, Rohelcund, and Delhi districts. In 1836 the millesimal ratio of deaths from fever at Bermuda was Г5, as against 00 in 1835, and that from dysentery and diarrhoea 7.7, as against Г5. At New Orleans there was no yellow fever. In 1837, at Bermuda, the mortality from fever rose to 4.8 per 1,000 ; and the yellow fever appeared in one of the islands, but was confined to it. At New Orleans this year there was a severe epidemic of that form of the disease, and it prevailed extensively in Cuba. In 1837 the wave would pass into the zone beyond the isoclinal 70° N. The ratio of deaths per 1,000 from fever at Nova Scotia, rose from 0-5 in 1836 to 30. In Canada too thero was an increase, though to a less extent. In Great Britain and Ireland typhus became remarkably prevalent this year, and continued into the following one, but with diminishing intensity, except in Edinburgh. The Foot Guards and Cavalry on the home station showed a considerable increase of mortality from fever in 1837. The Infantry also had a high rate, though less than in 1836; but as in 1837, for the first time, the whole of the Infantry serving at home were brought into the returns, while up to 1836 inclusive the depots of regiments serving in the West Indies only were included, it is possible the result may have been affected thereby. In 1838, however, the mortality of all that description of force was considerably less. In 1838, from March to the end of June, intermittent fever prevailed to a very unusual degree for 40 or 50 miles along the Angcrman river in Sweden. Typhus and jaundice were very frequent in Iceland; and in America, in the Mauriac basin, at the south-west angle of Lake Erie, there was a very severe epidemic of autumnal fever with yellowness of skin, closely resembling the yellow form of the disease.

The wave following the above would pass the isoclinal 53° S. in the beginning of 1834. At Mauritius the mortality from fever remained high, as in 1833, and that from dysentery and diarrhoea increased somewhat. There was no return for the Cape Frontier this year. There was no death at Cape Town from fever, but the following year a considerable mortality for that station. In 1836, when the wave would pass into the zone north of the isoclinal 0°, Ceylon showed a lower mortality from fever, as well as from affections of the bowes, than the previous year; and in 1837 that from fever diminished in MEDICAL REPORT FOR 1864. 463

much greater proportion. There are no records available for the portion of this zone on the Atlantic coasts this year. In 1837 the wave would pass the isoclinal 30° N. This year the plague was very severe in the districts of Marwar, Meywar, and Ajmer; and there were much intermittent and remittent fever in Upper India, and the fever with yellowness to the eastern parts of the country. Yellow fever, of which the probable approach had been foreshadowed by a single case in 1835, broke out at sierra Leone as a very severe epidemic in April. In July it appeared at the Gambia, and in August and September at Goree. In April too it commenced at George Town, Demerara, on the west coast of the Atlantic; and was experienced severely in Barbadoes, Martinique, Dominica, and Jamaica. In 1838 the wave would pass into the next zone beyond the isoclinal 53° N. The mortality this year, both from fever and bowel complaints, was very low in the Ionian Islands and Malta; but at Gibraltar the ratios from these rose from 0.9 and 0.9 in 1837 to 4.7 and 2.4 respectively. In Bermuda there was no death from fever among the troops, and at New Orleans none from yellow fever. The last epidemic of plague which occurred in Constantinople took place in 1838. The wave would pass into the zone beyond the isoclinal 70° N. in 1839. The ratios of mortality declined considerably this year at Nova Scotia, but in Canada they were but little diminished. In England and Scotland, in 1839, there was less fever than the previous year; but the Fever Hospitals in Cork and Dublin showed an increase of about a fourth on the admissions of 1838. In 1840, throughout England, the deaths from fever, according to the Registrar-General’s returns, were Г12 per 1,000, having been 1-04 only in 1839; and at Cork and Glasgow fever seems to have been more frequent also. The returns among the troops are to the same effect. All showed a diminution in 1830, but in 1840 the Foot Guards and Infantry both had a great increase.

The next wave would leave the isoclinal 63° S. on 1st January, 1836. At Mauritius this year, while the mortality from affections of the bowels retained almost its previous rate, the ratio of deaths from fever was 2.6 against O’O in 1835. At the Cape the ratios were ГЗ and 1.3 respectively, against 3.4 from fever in 1835, with none from affections of the bowels. The wave would pass the isoclinal 0° in the beginning of 1838. The deaths per 1,000 among the troops in Ceylon, from fever, in 1837-8-9, were 0.9, 0.9, and 1.0 respectively; all very low, and showing no prevalence of this disease. At Ascension this year there was a severe outbreak of yellow fever. The disease commenced in the end of March, after heavy rains on the 16th and 17th of that month, preceded by some years of dry weather. The wave under consideration would reach Ascension early in January, consequently the island would be fully under its influence in the end of March, when the ground began to dry after the heavy rain, and malaria tc be evolved under the action of a nearly vertical sun. In the year ending 31st March, 1839, the mortality from fever among the officers of the army, at Sierra Leone and the Gambia, was in the ratio of 3-5 per 1,000 of mean strength; and ia that ending 31st March,’1840, and consequently embracing the sickly period of 1839, the rate rose to 102 per 1,000. In the West India Command, in 1830, fever seems to have been less prevalent than in 1837 and 1838, though still frequent; but in Jamaica the ratio of deaths per 1,000, which in 1838 was 22.4, rose to 44.3. The wave would pass beyond the isoclinal 63° N. in 1840. In the Ionian Islands the mortality from fever of the previous year was slightly increased, and that from bowel complaints to a less extent. At Malta the ratios from both were diminished; but at Gibraltar that from fever rose to 2.0 from 0.0 in 1839, and that from bowel complaints to 1.2 from 0.7. At Alexandria, in 1839, there were 19 deaths only from plague; in 1840 these rose to 679. These facts show the existence and passage of the wave to the northward in the usual manner.

It is needless to go further into the detailed examination of these waves. Those traced above are sufficient to show that their progress is regular, and that the two-yearly period, with the limits assigned to them each year by the isoclinals so frequently mentioned, represent the results obtained from so many points with a degree of accuracy that could scarcely have been anticipated. Though the detailed examination has embraced little more than twenty years, yet as the succession of waves evidently depends on some general influence connected with terrestrial magnetism, there can be no hesitation in applying the principles developed above to the explanation of the epidemics which have excited much discussion among the members of the medical profession, and which are as yet involved in obscurity, provided they occurred at periods not so far removed from 1838, the date to which the isoclinale in the chart are brought up, as to introduce material error, and to render these inapplicable. It may be well to notice some of these.

In 1843 there was a very severe outbreak of yellow fever at Bermuda. Retracing the wave backwards, it is found it was in operation in the West Indies in 1841. From the data given by Blair (see Table II), it appears that in 1840 the millesimal ratio of deaths among the white seamen at George Town, Deraerara, from yellow fever, was 15.6; in 1841 this rose to 32.5, and the following year continued at 32.1, after which it declined to 5.8. In 1841, in Barbadoes, where I then was serving, there was a considerable mortality among the troops, from the same disease, towards the end of the year; and at Dominica a detachment of the 92nd Regiment suffered so severely from it that it was withdrawn. This year too a battalion of the 60th Rifles went from the Ionian Islands to Jamaica, where it suffered very severely, the millesimal ratio of deaths from fever among the troops there, which in 1840 was 52.l, having risen in 1841 to 352.9. In 1842, at Bermuda, there was a ratio of deaths from fever of 64) among the troops, as against 3.4 in 1841, showing the disposition to a more severe description of fever, as in 1818; and in 1843 this was magnified into a very fatal epidemic, causing a mortality of 12Г6 per 1,000, a course exactly parallel to that which had occurred 24 years before. There was very little yellow fever at New Orleans in 1843, but at Charleston, Mobile, and Vicksburg on the Mississippi, the disease was very prevalent.

In 1815 the sickness broke out in the “Eclair” on the coast of Africa, which has since led to so much controversy. One argument strongly insisted on by those who maintained that the epidemic which appeared at Bona Vista that year arose from the communication with her crew labouring under yellow fever, was, that there was no evidence of an epidemic constitution being in operation, and hence its aid could not be invoked to account for the appearance of the disease after she had left. By reference to the chart it will be seen that Bona Vista lies in the zone between the isoclinal 30° and 53° N.. and, like Sierra Leone, will experience the first part of each wave in the odd years. The points in this neighbourhood for which there are records are Sierra Leone, Bathurst on the Gambia, Goree, St. Louis on the Senegal, and Bona Vista. The first part of the wave would reach these as follows :—

Sierra Leone about 1st January.

Bathurst „ let May.

Goree .. ,, 1st June.

St. Louis „ 25th June.

Bona Vista „ 15th August.

And fever may be looked for at each after these dates, at the season when the local causes come into operation. Accordingly it is found that epidemics of yellow fever commence at Sierre Leone in the end of March or April ; that of 1847 began in the end of June. The outbreak at Bathurst in 1847 commenced among the inhabitants generally in the end of July, the first death among them having occurred on the 30th of that month. Mr. Tebbs, the Colonial Surgeon, the first case in the colony, died on 30th June. The first death we know of at Goree was on the 16th August—that of a person who left Bathurst a few days before. Soon after this, however, other cases took place in persons who had not been away from Goree. In all these instances the epidemic commenced from two to three months, or more, after the arrival of the waves when the local causes of disease seem to have become active.

It has been mentioned above that a single case of yellow fever proved fatal at Sierra Leone iu 1835, and that on the advent of the next wave, in 1837, the very severe epidemic took place, the appearance of which at the Gambia and Goree has just been noticed. In 1845 and 1647 a parallel series of facts occurred. In the former year three cases of yellow fever presented themselves at Sierra Leone, one on the 6th or 8th August, another on the 15th, and a third on the 16th, all of which proved fatal. The “Eclair” left Sierra Leone on 23rd July, when the subjects of the last two attacks had not arrived in

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MEDICAL REPORT FOR 1864. 465

the colony.* It may be doubted by some when the cases on board that ship first assumed the character of yellow fever. I quito agree with the opinion of the compiler of the Reports on the Health of the Navy, that some of those which occurred while she was at anchor off the Seabar, to the south of Sierra Leone—that of the stoker on 23rd May, and of Field on 4th June, for instance—were not to be distinguished from those that occurred subsequently iu short, were really cases of yellow fever. There is no doubt too that in 1845 cases of this disease occurred on shore at Sierra Leone, altogether independent of the “Eclair ¡” and, as in 1837, these were followed by a severe epidemic of the same disease in 1847.

As to the extent of operation of the epidemic cause, the details given above show this to be far more general than has hitherto been supposed. The disease arising under its influence appeared both in the “Eclair” and on shore at Sierra Leone, quite independent of each other. • It sprang into existence also in Bona Vista after the visit of the “Eclair;” but though, as shown above, the wave must have reached that island towards the end of August, and she left it on 13th September, the disease did not commence among the inhabitants, who had no communication with her or her people, until 12th October, the usual unhealthy season there, and after much ram had fallen, exactly as took place in Ascension in 1838. That the wave experienced at Sierra Leone and Bona Vista in 1845 did not become extinct, there is the most unequivocal evidence ; for in 1846, when it was to be looked for in the zone to the north of the isoclinal 53° N., an epidemic of fever resembling, if not actually, yellow fever was experienced at Santa Cruz in Teneriffe; and the mortality among the troops from fever in the Ionian Islands rose from 2.5 in 1845 to 6.8 per 1,000 in 1846 ; at Malta, from 1.1 to 3.0; and at Gibraltar, from 9.9 to 6.7. At the last-named station, one case presented yellowness of conjunctivae and skin, and so much resembled yellow fever that an epidemic was anticipated.! In 1847 this wave extended to the British Islands, leading to a great development of febrile disease. Thus it appears the pandemic cause passed in successive years, according to the general course of the waves, from Sierra Leone and its neighbourhood to the south of Bona Vista in 1845, to Teneriffe and the Mediterranean stations in 1846, and to England in 1847; and under its operation yellow fever appeared in the “Eclair” and on shore at Sierra Leone, independent of each other; that either this, or a disease closely resembling it, broke out at Teneriffe in 1846, and there were indications of the same at Gibraltar. With these facts so clear it is difficult to avoid the conclusion that the epidemic at Bona Vista was owing to local causes under the operation of the more general wave, as in the “Eclair” and on shore at Sierra Leone, and was independent of the visit of the “Eclair” altogether.

In 1849 yellow fever made its appearance in Brazil, after many years absence from that country. The places at which the disease showed itself may be divided into two categories. These with the dates of the first cases among the residents were—

Bahia lat, 13° S. 3rd Nov. 1819.

Pernambuco , 8° 8. 25th Dec. „

Rio Janeiro ,23° S. 28th Dee. „

Para Io S. — March, I860.

Porto Allegro 31° S. — April, 1851.§

The first three lie to the north of the isoclinal 0°, and towards the end of the odd year the first part of the passing wave would be between the isoclinal 30° N. and 53° N., near the latter; and the line of demarkation between this and the following wave would still be at some distance to the south of it и . The epidemics at these places therefore occurred under the latter part of the wave in the second year. From the information at my disposal, the epidemic seems

* These facts I ascertained at Sierra Leone subsequently. The details are given by Bryson, Account, &c, p. 102, et seq. t Bryson, Account, &c, p. 101.

I Statistical Report on Health of Troops in Mediterranean, 1837-46, p. 83. § One case only.

to have declined at Bahia in the end of February, 1850, and at Pernambuco somewhat later. The line of separation between this and the following wave would reach Bahia about 1st March of the even year.

Rio Janeiro is so situated between the isoclinals 30°8 and 0°, that it would come under the first part of the wave in the odd year about 1 st August, the cold and healthy period in the southern hemisphere, when yellow fever was scarcely to be looked for. After warm weather set in, however, the disease commenced on 28th December, attained its height in March, declined in May, and ceased in July. As mentioned above, one case was met with at Porto Allegro in April, which, it will be seen by the chart, is in the same zone as Rio Janeiro. Yellow fever appeared at Rio again in the early part of 1851, being the second year of the same wave there, and several times since that date.

In 1853, when the disease was again prevailing on the coast of Brazil, a fever resembling it made its appearance at Monte Video. This place, as may be seen by the chart, is situated but little to the south of the isoclinal 30°3, and consequently would be reached by the advancing wave towards the end of the even year; and, in accordance with what has been found in similar cases, the outbreaks of fever are to be looked for in the early part of the following or odd year. Though doubts were entertained whether the disease of 1853 was true yellow fever, the possibility of this occurring at Monte Video was quite established by the epidemic of 1857 there when this form of fever broke out about the middle of February, and continued to the end of May, carrying off about 1,800 persons.

The progress of yellow fever along the Pacific coast of South America, within the last quarter of a century, is quite in accordance with what has been mentioned regarding it on the Atlantic side. The disease became epidemic at Guayaquil in latitude 2° S. in 1842. This city is situated between the isoclinals 0° and 30° N., and would experience the first part of the wave about 1st June of the even year, which may be regarded as the cool season in that climate, and the time least likely for fever to appear. A schooner, “La Reina Victoria,” ballasted with “wet gravelly mud,” reached Guayaquil somewhere in the beginning of September, 1842, from Panama, having lost three passengers on the way, after her arrival three of the crew were landed sick with yellow fever, the last two on 7th September: all of these died, and, it is inferred, communicated the disease to those within the immediate vicinity. Carpenters and coalheavers who had direct communication with the vessel, as in so many other instances, were attacked ; and it is said they propagated the disease to others, so that in less than twelve days more than forty persona had died. The schooner’s position was then altered, and her ballast removed, when fever broke out anew, so that whatever may be thought of the evidence of the sick, from her communicating the disease to others, there was strong evidence that the ballast had caused it in the vessel herself, and to others exposed to the effluvia from it on its removal. Sometime then seems to have elapsed, as it was not until after the 9th October the disease began to spread, it culminated in the end of November, and by 8th December its violence was abating* Yellow fever seems to have prevailed here, more or less, up to 1845. The coincidence of the general outbreak with the first sickly season after the arrival of the wave is here also distinct, and its delay until then, notwithstanding the supposed importation at an earlier period, must be significant.

Yellow fever appeared in Peru ten years later; the circumstances connected with its origin have been described by Dr. A. Smith,t from which the following has been taken. In 1852 a febrile complaint, new to the inhabitants, prevailed very generally in Peru, though it caused little mortality. At Lima it commenced early in January, and disappeared by July. An elderly German woman who had had an attack of this disease, after a lull of apparent convalescence, died suddenly on 16th February, with melanitic stools. In February, 1853, a fever resembling that of 1852 closely, but with a greater disposition to hemorrhage, commenced at Lima, and continued to July as before. This year one case proved fatal on 16th April, one on 14th May, and one on 19th May,

* Transactions of Epidemiological Society, vol. i., p. 24,4-5.

t British and Foreign Medico-Chirurgical Review, vol. xxxiii., p. 186, et seq.

MEDICAL REPORT FOR 1864. 467

all of them with black vomit. Dr. Smith states these were the first declared cases of yellow fever in 1853, and they had no communication with each other. A few more isolated cases seem to have been observed up to the period of extinction of the epidemic in July. In September, 1853, the disease appeared at Yurui, latitude 90° S., among the Andes, 3° north of Lima; at the same time it was prevalent under the first part of the same wave in Jamaica, at Puerto Caballo, and in several of the West India Islands. In the last week of December, 1853, a few cases of decided yellow fever appeared at Callao (the port of Lima), and early in January, 1854, it sprang up in Lima with extraordinary generality, and continued in force to the end of March; by the middle of April it had nearly exhausted itself. At lea on the coast, in 18° 28′ S., yellow fever was prevalent in March, April, and May, and there were a few cases at Islay in 16° 32′ S. in April and May. Lima, as previously stated, shows the greatest prevalence of fever in the early part of the even years, which is quite in accordance with the details here given. The gradual change in the form of disease is particularly deserving of notice ; a form of fever new to the medical practitioners presented itself in 1852, the first year of the wave, with a single case of melcena; the second year a few more cases presented this disposition more developed, and assuming the more common form of black vomit; and the first year of the following wave the disease generally presented the character of yellow fever. Parallel facts have already been mentioned in connection with Sierra Leone and Gibraltar, and it had been observed in Brazil that the Dengen or Dandy fever had prevailed every season for four years preceding the eruption of yellow fever there in 1849. Were the phases of disease watched as closely elsewhere as they seem to have been at Lima, such a transition would be found more common than is generally supposed. ”

In 1855, the second year of the “wave, yellow fever was very severe at Islay on the coast, in April and May, and it prevailed in the towns in the mountains at various periods between April and October. Lima this year did not suffer from yellow fever, but intermittents were epidemic, and appeared in wards of the town scarcely ever before affected with ague. In the mountainous districts at the lesser elevations, and in some of the valleys, the disease seems to have presented much the usual character; at a greater elevation there seemed a transition to the characters assigned by Humboldt to the matlazahuatt of Mexico, and, higher still, at Huancavilica (12,969 feet above the sea), the fever was much more protracted than lower down, and resembled more the endemic typhus called fabardillo. In 1855 the wave which has just been traced over Peru passed into the zone between the isoclinals 30° and 55° N., and this year the matlazahuatt prevailed in Mexico, and in 1856, the second year of the wave in this zone, yellow fever was frequent in Jamaica, and invaded the military station of Newcastle at an elevation of from 3,600 to 4,100 feet above the sea. It was severe also at Havanna and Port-au-Prince, in St. Domingo. This year too, under the first part of the same wave, a few cases of yellow fever appeared at Oporto; and about the beginning of September in Lisbon, when 87 died from it. The following year the disease commenced there again in July, and began to subside in October. A few cases occurred at Ferrol and Corunna also in August, 1857.

In October, 1855, fever appeared at Cuzco, lat. 13° 30′ S. (11,370 feet above the sea), and from November to May, 1856, proved very fatal, carrying off about a-third of the population. In 1856 Lima was again visited by yellow fever, which caused many deaths. This outbreak was owing to a fresh wave which, in its progress northwards, would reach Cuzco about 1st November; here, accordingly, the fever became aggravated that mouth, while everywhere else in the mountains it had then diminished very much or quite disappeared, and it reappeared at Lima at the usual season, then supplanting the intermittent of 1855.

These facts suffice to show that the recent epidemics of both the east and west coasts of South America, and those of Portugal, are quite in accordance with the principles developed in the course of this paper from the consideration of the progress of disease in other parts of the world. Taking the whole facts, more conclusive evidence of the existence, period, and rate of progression of the waves could scarce have been expected, while their limitation by lines of equal magnetic dip affords the strongest presumption of their being intimately connected with terrestrial magnetism.

The character of the waves has been illustrated by epidemics at various points on land, as these have the advantage of being fixed with a population nearly stationary, and the diseases prevalent in them for considerable periods are known; but it is reasonable to conclude that their influence, which is so diffused and so regular in its action, should be manifested at sea also, whenever circumstances favourable for the development of their powers are present. To their influence may be fairly attributed many of those severe outbreaks of fever which have occurred in emigrant ships, as, for instance, the typhus which appeared in several of those from the British Islands to America in 1847, when during the whole voyage they would be little, if at all, to the south of the isoclinal 70″ N., and under the full force of the wave which passed that on 1st January, 1847, and was then leading to so much fever on both sides of the Atlantic. A similar tendency to fever was observed in vessels direct from Europe, when they were sufficiently to the south to approach the coast of Brazil in 1850, and many other instances will occur to those familiar with the history of disease on board ships, which have sailed with their crews and passengers to all appearance in health, but have become very sickly before the termination of their voyage. The results may be varied somewhat as the vessel runs from east to west, or vice versa, in the same wave, or proceeds from north to south, or in the opposite direction, and crosses several; in the former case the disease may be nearly continuous, in the latter there may be shorter outbreaks separated, more or less, from each other by intervals of comparative immunity. These are cases which seem explicable on this supposition only.

V. Further parlicxdars allowing a Connection of Terrestrial Magnetism with Epidemics of Fevers.

The evidence to be adduced here is less complete than that given above; but, nevertheless, there are a number of facts showing a remarkable coincidence, at least, between magnetic phenomena and epidemics, which deserve special mention, and which may ultimately prove to be intimately concerned in their production.

The first point deserving of notice is that the magnetic intensity in the southern hemisphere is greater than in the northern; a fact which may be connected with the origin of the waves in the southern hemisphere and their regular passage to the northern.

Magnetic storms, as they are called, seem in some way connected with the intensity of epidemics. These storms consist of great and rapid alterations of the force of the magnetic elements, causing the instruments to oscillate to a much greater extent, and in a more irregular manner than is usual for the hour of the day, or season of the year. It has been observed by Sabine that these storms recur iu a regular period of about ten years, the minimum occurring in the years three and four in each decade, and the maximum in the years eight, nine, and ten, while the transitions from the minima to maxima, and vice versa, are rather abrupt. Sabine has further drawn attention to the fact of these magnetic storms coinciding in period and epoch with the frequency of the solar spots. Those who have examined the records of epidemics may recollect that the years seven, eight, and nine, in each decade in the present century, have been characterised by an unusual prevalence, and severity of fever in many parts of the world. Severe fevers are occasionally met with in the years three, four, and five of the decade, but they do not seem so diffused as in those numbered seven, eight, and nine. The facts of these periodical aggravations of fever being accompanied by a disturbed state of the earth’s magnetism, and of their being apparently connected with unusual disturbance of the sun’s photosphere, open up a field of enquiry of the deepest interest, which bids fair to throw into the shade the wildest fancies of the astrologers.

These details show a connexion between magnetic excitement and the periodic aggravations of febrile diseases thorughout a large portion of the world, more especially in the years seven, eight, and nine of the decade; but they do not indicate the steps in the conversion (to use an expression more in

MEDICAL REPORT FOR 1864. 469

common use) of the magnetic force into the active cause of disease, and until much more is known of th<î laws of terrestrial magnetism, and of the immediate causes of magnetic diátiirbances, we will not be in a position to do more than point out their connection in a general manner, though, even here, some facts have been ascertained which promise a rich harvest if followed up.

It has been deduced from an examination of the regularity of the indentations in the curves, traced by the magnetic registering apparatus at Kew, that, during the magnetic storms, the disturbing forces of the magnetic elements are such as to affect all these, or one of them, either alone, or more than the others. The former are by far the most frequent, and have been attributed to a cosmical influence, while the latter are most probably dependaut on a terrestrial one.* In connection with this, though derived from observations altogether independent, may be noticed the effects of magnetic storms on electric telegraph lines. During theso storms earth-currents, as they are called, are often so strongly developed that the ordinary battery employed for working the lines is insufficient to give precise indications, even at a moderate distance. Mr. Walker, the superintendent of the electric telegraphs of the South Eastern Railway, states that 1847-48 were periods of great activity of these currents, while 1849 was one of almost inaction, and this state of quiescence continued apparently until 1856, when they again excited attention, and a large number of observations accumulated in 1857 to 1859 ;t but I have not met with an abstract or reduction of them. The” coincidence of these currents in 1847-8 with the epidemics of those years cannot be fortuitous; and these cessations in 1849, though by the observations of declination at Toronto in that year, it is apparent magnetic disturbances still continued active,! not only goes to support the opinion noticed above that both cosmical and terrestrial influences are concerned in producing these, but that each may to some extent act independently of the other. It also throws some light on the fact that, though the magnetic storms continue into the tenth year, and even beyond it, yet the seventh, eighth, and ninth years are those in which the general aggravation of fever occurs.

Dr. Augus Smith, of Manchester, has stated that ground giving out malaria is alkaliue.§ If this be always so, from the well-known influence of electric currents in determining the positions of acids and alkalies, after decomposing the neutral compounds which these previously formed, some clue may be found to unravel this hitherto complicated and obscure subject. These hints may suggest the direction in which enquiries must be made, but the points they refer to, and the deductions these will support, can only be established by a full and searching investigation.

If the reader will revert to Table I he will find that in 1823, while there was a severe epidemic of yellow fever at Sierra Leone, the West India Islands and Jamaica presented less mortality from that class of disease than for several years, either before or after. In 1829 there was a similar outbreak at Sierra Leone, with a minimum of mortality both in the West Indies and Jamaica, In 1859 a parallel series of facts presented themselves, there having been a severe epidemic of yellow fever at Sierra Leone, Bathurst on the Gambia, and Goree, while in Jamaica there was very little fever; but 1824, 1830, and 1860, were all more sickly in Jamaica than the years immediately preceding. Meteorological conditions may have had something to do with the immunity of the West Indies and Jamaica in 1823 and 1829; but as to 1859, though in Jamaica at the time, and constantly engaged with meteorological observations, I was unable to detect anything very unusual, and I am not aware of any peculiarity, either in the habits or condition of the people, to account for the immunity they enjoyed. Another feature which presents itself in the course of epidemics is not only that yellow fever may be prevalent in the customary localities, or even in others where it is rarely met with, but, about the same time, in countrks remote from these, fevers of a different form maybe very frequent, and accompanied by yellowness so generally as to characterise the epidemic.

* Stewart, Proceedings of Royal Society, vol. xi., p. 7.

+ Proceedings of Roynl Society, vol. xi., p. 105-8.

J Sabine, Magnetic Observations, Toronto, Introduction, p. xxii.

§ Year Book of Medicine and Surgery (Sydenham Society) for 1861, p. 463.

Examples of this are found in Iceland and the coast of Holland in 1826, with a few cases of yellow fever at Gibralter that year, and in Iceland in 1638, with a corresponding disease to the south-west of Lake Erie. Though these facts are clear and unmistakeable it is not easy to explain them ; it is possible that the remarks by Stewart given above, as to the combination of cosmical and terrestrial influences in producing magnetic disturbances, may ultimately throw much light on them, but until the nature of the terrestrial influences in question be more fully known, and the limits of their operation determined, so that the results may be compared with the epidemics over a sufficiently extensive portion of the world, it would be useless endeavouring to push this speculation further. It is deserving, however, of the most searching enquiry.

Since writing the above it occurred to me to examine how far the principles developed in this paper were borne out by the records handed down to us of the epidemics of former ages. A cursory examination of these since the fourteenth century, inclusive, will show that in Spain, Italy, south of France and of Germany, the epidemics of fever, or plague, were more frequent in the even years, while in England, north of France, and of Germany, they were more common and more severe in the odd years, exactly as in the present day.

The earliest observations on the magnetic dip were made in 1576 by Norman, who found it 71° 60′ in London. The next observations then were by Graham in 1720, when he found it 74° 42′. Between these dates the dip had been found in Paris, in 1671, to 75° 0′, and as it was generally about Io greater at London than at Paris, it is likely that at London, about 1670, it would have been 76° nearly. The dip thus increased at London for nearly a century from Norman’s first determination, since which it seems from the observations there and at Paris to have diminished pretty regularly.

On the assumption that the advancing edge of the pandemic wave makes the isoclinal 70° N. on the 1st January in the odd year, and passes over the space between that and the isoclinal 80° N. in a year, the wave would reach 76° by 8th August, which would still permit a severe epidemic being developed in England in the same year. When the dip approached more to that laid down in the chart attached to this paper, the cause of the waves would agree more closely with what is stated above ; but inasmuch as the form of the isoclinale much to the east or west of England, at the earlier periods, must be matter of conjecture, it will not do to assume the inflexions of these in the chart will apply to those periods.

The position here taken is borne out by the monthly records of the mortality from plague in London, in 1665, which are as follows :—

[table]

Though the materials for plague were evidently abundant, and numerous deaths took place from it in July, yet the advent of the wave in August is distinctly marked by the rapid expansion of the mortality in that month.

MEDICAL REPOET FOR 1864. 471

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TRANSACTIONS OF THE EPIDEMIOLOGICAL SOCIETY OF LONDON VOL. III.

FURTHER OBSERVATIONS ON THE INFLUENCE OF PANDEMIC WAVES IN THE PRODUCTION OF FEVERS AND CHOLERA.

By ROBERT LAWSON,

INSPECTOR-GENERAL OF HOSPITALS.

[Read 2nd March, 1868.]

About ten years ago, while I was in charge of the Medical Department of the Army in Jamaica, I commenced an examination into the records of mortality at the various military stations in that island, to ascertain whether they indicated the operation of local causes that might be removed. I had proceeded but a little way before it became apparent that a cause of far more extensive operation was concerned, and, that until its laws were detected, there was no probability of any satisfactory deduction being drawn from the history of disease at the respective stations. I accordingly endeavoured to trace the course of epidemics, but, after a long consideration of all the evidence within my reach, was unable to fix on any law, though the fact that the epidemic influence was often experienced over a large extent of the earth’s surface at the same time was clearly made out.

In the end of 1861 I was induced to examine into the course of fever in Jamaica again, and had scarcely begun it when the former difficulty presented itself, and the inquiry was immediately turned in that direction. After much consideration I was led to the conclusion that epidemics proceeded regularly from south to north, and that they might be traced from the Cape of Good Hope to Iceland. They succeeded each other at intervals of a few years, and often affected places far distant in longitude, and their resemblance to a succession of waves led to their causes being designated Pandemic Waves.

As the course of these waves seemed uninfluenced by atmospheric currents, it was clear they must be owing to some terrestrial force, and their appearance at Mauritius and the Cape the same year, and their subsequently manifesting themselves at more northerly latitudes on the eastern side of the Atlantic than on its western shore at the same time, taken in connection with the position of one of the magnetic poles to the north of Canada and the south of Australia, rendered it probable that the force was magnetic.

I proceeded to the Cape of Good Hope in the end of 1862, and after some months was enabled to revert to this subject. After encountering many difficulties which it is unnecessary to detail here, I was enabled to prepare a chart indicating the progress of the Pandemic Waves, year by year throughout their course, by lines of equal magnetic dip or isoclinals. A copy of the chart, accompanied by some explanations and a detailed examination of epidemics of fever, appeared in the sixth volume of the Statistical Reports on the health of the army for 1864. A subsequent paper containing an examination of the progress of cholera during the present century is ready for publication, and may most likely appear in the forthcoming volume of the army Statistical Reports.

Since my return to England I found there was a map of the Isoclinal Magnetic Lines by General Sabine for 1840 in Johnston’s Physical Atlas, and I have altered the original chart in conformity with this. A copy of the new chart on a large scale has been prepared for the Epidemiological Society, and it has been suggested that a notice of the principles on which it is formed, and their application to the elucidation of epidemics, would constitute a fitting accompaniment. In what follows I will endeavour to convey the leading principles as shortly as possible, and illustrate them by a few examples. Those who are anxious for fuller details are referred to the original papers.

I. PERIOD OF THE WAVES.

If the records of disease at any place when fever constitutes a considerable portion of the sickness be examined, it will be found that, for the most part, the serious outbreaks occur either in the odd, or in the even years, according to its geographical position. There may be epidemics in the alternate years, but far more frequently they show themselves in the year peculiar to the station. Thus at Sierra Leone there were some cases of yellow fever in 1817, a. severe epidemic in 1823, another in 1829, one case in 1835, a severe epidemic in 1837, three cases in 1845, another severe epidemic in 1847, and another again in 1859, all of them odd years. In Jamaica there were very severe epidemics of yellow fever in 1819, 1825, 1827, 1831, 1837, 1841, 1853; there was considerable mortality in the even years, occasionally, from fever, but, as will be shown hereafter, the excess fell on the odd years. Yellow fever appeared at Gibraltar in 1804, 1810, 1813,1814, 1828, besides threatening to do so on several other occasions ; of the five periods four are even years, and one only an odd year. These facts show the waves to have a period of two years, or of some multiple of that, but on the whole the two-yearly period seems to represent them best.

The relative influence of the first and second years of the wave is brought out very prominently by the mortality among the troops in Jamaica from 1817 to 1836. In abstract XXX of the Appendix to the Statistical Report on the Health of the Troops in the West Indies for these years, the deaths from all causes, in the regiments of the line in Jamaica, are given for each month of every year. There are no means for separating the mortality from fever from that arising from other causes ; but as the deaths from specified diseases amounted to 121-3 per 1,000 of mean strength, while those from fever alone constituted 101-9 of this ratio, or five-sixths of the whole, and it is well known that the excess of mortality in all the epidemics arose from fever, the fluctuations of the death rate may be taken to represent pretty accurately the influence of the Pandemic cause, acting of course through local causes and personal susceptibility.

Arranging the deaths for the twenty years by months, they are lowest from March to June inclusive, and highest in November ; and if those for the twelve months commencing with March of the odd years be placed together, and those commencing with March of the even years similarly treated, and their sums taken, the aggregate mortality each month during the first and second years of the wave will be obtained. These numbers are as follow :—

[table]

These figures if projected in a curve bring out clearly the much greater activity of the causes of fever under the first year of the wave than under the second; but it is obvious from the latter that a considerable epidemic is even then possible, though on a series of years the excess of mortality occurs under the first year. The form of the curve for August and September in the first year, as compared with its position up to July, and subsequent to October, indicates a disturbing cause, which on examination was found to arise from the excess of mortality in those months in the 50th and 92nd Regiments (just arrived from England) in 1819, and in the 84th (also recently from home) in 1827. There was a similar disturbing cause in the months from March to June of the second year, with the 33rd and 91st Regiments in 1822 (mostly from fever likewise), and with the 77th in 1825. Subtracting the deaths in these corps for twelve months after their arrival from the aggregate monthly mortality already given, the following numbers are obtained :—

[table]

These results show a regular progression from the minimum in April to the maximum in November the first year, and a less symmetrical one from the minimum in April to the maximum in December of the second.

There are no materials in the Statistical Reports on the health of the army to permit of the progress of fever from month to month being traced for other stations as for Jamaica, but the deaths from fever being given for each year, these have been reduced to their millesimal ratios to the strength, and those for the odd years, and those for the even added together, and divided by the numbers of these respectively, so as to obtain mean annual results. The statistics for the Home Station embrace seventeen years, for Gibraltar twenty-nine years, the other Mediterranean and the American stations thirty years, Ceylon, Jamaica, and West Indies twenty years, Mauritius, and Cape Town nineteen years, and Cape Frontier thirteen years only. These stations with their mean annual mortality from fever per 1,000 of strength, taking them as they come under the influence of the advancing wave, are—

[table]

The ratios for the even year at Gibraltar, and for the odd at Bermuda, are materially increased by the mortality in 1828 at the former, and by the epidemics of 1819 and 1843 at the latter ; but if for the excessive death rate in these years, that of the highest in another even or odd year, respectively, be substituted, the mean annual ratio for the even year at Gibraltar comes out 3 26 as against 152 for the odd year, and at Bermuda 531 for the odd year as against 3-31 for the even one, still showing the excess as in the first instance.

The period when fever appears at the different stations is an important consideration in this inquiry. At Mauritius, the Cape, and in the southern hemisphere generally, the local causes seldom present any marked activity before the beginning of December; fever seems to be most frequent in February and March, and then to decline to July, or even to extend into August. In Ceylon, from September to March, there is little mortality from the disease; it attains its greatest force in April, and declines through the following months to August. The course of mortality in Jamaica is obvious from the details already given; and that of the Windward and Leeward Islands, or the West Indies as they are denominated in the military returns, does not seem to be materially different. In the Mediterranean and American stations, and Bermuda, fever commences to increase in June; it seems to culminate under ordinary circumstances in August, and then to decline. At Gibraltar, however, though cases of yellow fever have been met with as early as the middle of July, it was not before the end of August that the disease spread, and it attained its greatest height towards the end of October.

II. PROGRESS OF THE WAVES.

As mentioned above, the waves move from south to north. They take five years to go from the Cape of Good Hope to England. Any period of the year might be fixed on to lay down their position. I have selected the 1st of January as the most convenient and best suited to the statistics which were available. The lines on the chart are lines of equal magnetic dip or isoclinals, and were selected to represent the position of the advancing edge of the wave from year to year. Those on the chart are 70°, 53°, and 30° south; and 0°, 30°, 53°, 70°, and 80° north. These represent the progress of epidemics with unexpected accuracy, but it is quite possible that, as the records of disease assume greater precision at different places, it may be found necessary to substitute others more or less distant from them.

A febrific wave is supposed to start from the isoclinal, 70° S., on the 1st of January of a year with an odd number, and to overspread the zone between that and 53° in the course of the year. It will start from 53° on the 1st of January of the even year, and so on. As the waves are assumed to recur every second year, another will leave the isoclinal, 70°, on the next odd year, and will pursue the same course as that which preceded it. From this peculiarity it follows that the first part of a wave is experienced in any given zone, either always in an odd year, or always in an even one, and from this simple arrangement results that the wave on the 1st of January in the

[table]

Will leave the isoclinal [by the given degrees South or North.]

And the force of the epidemics is accordingly felt in each of these zones in the year peculiar to it, following that of the zone to the south of it, and preceding that of the one to the north.

There is an apparent exception to this in the case of Mauritius, the Cape, Ceylon, and Bermuda. The first three lie to the north of zones which are overspread by the wave in an odd year, and can be reached by it only towards the end of the year, while fever prevails in all in the early months, hence the excess of mortality occurs in these in the even year, the first occasion on which the local causes acquire their activity after the arrival of the wave. Bermuda, near the northern limit of a zone overspread by the wave in an even year, has its severest epidemics in the odd year following.

As the progress of the wave from year to year is regular, so its advance through any given zone seems proportional to the period of the year which has elapsed, and the position of the margin may be thus shown approximately. Applying these principles to the mortality at the different military stations given above, it is found that at Mauritius, and on the Cape frontier, the excess falls on the even year, in accordance with the theory. Cape Town is an apparent exception; this arose altogether from the high mortality in 1825 and 1827, when numerous deaths took place from typhoid fever, presenting the usual intestinal lesions, and which was distinctly traced to the causes now recognised to originate them, and on the removal of them, the disease, which was confined to certain spots, ceased. Ceylon agrees with the theory also. In the next zone, Jamaica affords the strongest support to it, but the West India Islands give an undecided result, the cause for which I have not been able to detect. As Sierra Leone in the same zone on the east of the Atlantic, however, agrees with Jamaica, there is every reason to conclude that there must have been something in connection with the West Indies which masked its development. In the zone beyond the isoclinal, 53° N., the Ionian Islands present a similar anomaly to the West Indies, while Malta and Gibraltar both give unequivocal support to the theory. Bermuda in this zone, as already stated, has the severest epidemics in the odd year, though they are not confined to that. Beyond the isoclinal, 70° N., the cavalry and foot guards, which at that period may be considered as having had almost their whole service at home, have their excess of deaths from fever in the odd year. The infantry, which from 1830 to 1836 included the men of the West Indian depots, mostly recruits, for the next ten years embraced the whole of the regiments on home-service, all of which had recently returned from abroad; this fact may have had something to do with the different result obtained for this portion of the force from those for the cavalry and foot guards. The ratios for Canada and Nova Scotia both show their predominance of mortality in the odd year, according to the theory.

III. THE INFLUENCE OF THE WAVES IN EXCITING EPIDEMICS OF FEVER.

The influence of pandemic waves in causing outbreaks of fever is manifest in two ways, viz.: firstly, under the operation of the same wave, in the same year, at points often very different in latitude and embracing in longitude almost half the circumference of the earth ; and secondly, in successive years, at points more and more to the northward, as the waves pursue their usual course. To illustrate these fully it is necessary to examine the records of disease at a sufficient number of distinct and widely spread stations for a series of years, when it will be found that many epidemics, which have hitherto been thought independent of each other, were local manifestations under the same general influence, and others which were considered accidental, and to account for which much labour has been expended and ingenuity displayed, fall into their place naturally as subordinate to the general law. A few such illustrations may be given here.

A wave is supposed to have advanced from the isoclinal, 53° S., on the commencement of 1816, but there are no data available for the Cape or Mauritius that year or the following one. The first indication of its operation is met with in in Ceylon 1818, when the mortality among the troops from fever, chiefly of the remittent form, rose to 133.8 per 1,000 of strength. At Ascension, where fevers occur in the same year as at Ceylon, the admissions in 1818 were twelve, six times more numerous than in 1817, and embracing nearly every man on the island; one death occurred, the symptoms, according to Burnett, being those of yellow fever. At Lima, in Peru, a large body of Spanish troops from Europe was assembled, among whom a severe fever, supposed to have been yellow, broke out in February 1818. The disease was not confined to Lima, but was met with as far as lea, in latitude 14° S. In 1819, this wave, extending from Ceylon to Peru, would overspread the zone beyond the isoclinal, 30° N. This year Pali plague was very severe in Cutch and Guzerat. The plague was epidemic at Susa, on the south of the Mediterranean. The mortality in the West Indies was less than in 1818 or 1820, but in several of the subordinate stations it was high, and at Demerara, one of these, where the form of fever for years previously had been the ordinary remittent, yellow fever appeared and proved very fatal. At Jamaica the mortality among the troops rose to 273-8 per 1,000. In 1820 when the wave would proceed beyond the isoclinal 53° N., the mortality in the Ionian Islands was low. At Malta it was more considerable for that place, and at Gibraltar it increased, while in the neighbouring parts of Andalusia yellow fever prevailed epidemically, and typhus was severe in the convict hulks at Toulon. At New Orleans where there had been a considerable mortality from yellow fever in 1819, it remained nearly as high in 1820. In 1821 the wave would proceed beyond the isoclinal 70° N. There was little fever in Nova Scotia this year, but in Canada the ratio of deaths was 2-8 as against 0’6 the previous year. At Bermuda the ratio rose to 143 from 3’0 in 1820, and at Norfolk in Virginia, and Baltimore, yellow fever showed itself. A fever denominated catarrhal prevailed in Iceland in 1821.

Another wave would advance from the isoclinal 53° S. on the 1st January, 1822. At Cape Town the mortality per 1000 this year was 2-3 as against 0-0 the previous year, and on the Cape Frontier it amounted to 4’8. There was no death from fever at Mauritius in 1822. In 1824 this wave would advance from the isoclinal 0°, and in Ceylon the deaths amongst the troops rose to 104 3 per 1000 from 200 the preceding year. The first Burmese war commenced this year, and the troops engaged suffered very severely from fever and dysentery, and that form of fever called Dengue appeared among them. The Ashantee war was also going on in 1824, in the vicinity of Cape Coast Castle on the West Coast of Africa; here there was excessive mortality among the Europeans employed in the field, from fever and dysentery. In 1825 the wave would enter the next zone; Dengue spread from Calcutta along the Ganges a considerable distance. Plague was very severe in Egypt. This year a body of white troops was sent to Sierre Leone and the Gambia, among which the mortality from remittent fever was excessive. There was a high mortality in the West Indies, but rather less than the previous year, but in Jamaica the ratio per 1000 rose to 287.8, chiefly from yellow fever. The wave would pass into the zone beyond 53° N. in 1826. Plague was prevalent at Constantinople this year; the ratio of mortality among the troops in the Ionian Islands rose from 8’3 the previous year to IPO. At Malta there was no increase; at Gibraltar it rose from 32 in 1825 to 42, and Hennen reports there were several cases of yellow fever. There was a high mortality from yellow fever among the troops in the Bahamas. In 1827 when the wave would enter the next zone, the mortality in Bermuda rose to 4-5 from P6 the previous year; in Nova Scotia it rose to 2’7 from 0-7, and in Canada to 4’6 from 3-2 in 1826. Typhus prevailed in Iceland in 1828, extending into the following year.

In 1845 the sickness broke out in the Eclair on the Coast of Africa, which has since caused so much controversy. One argument strongly insisted on by those who thought that the epidemic, which appeared at Bona Vista that year, arose from communication with the cases labouring under yellow fever, was that there was no evidence of an epidemic constitution being in operation, and hence its aid could not be invoked to account for the prevalence of the disease after she left. By reference to the chart it will be seen that, like Sierra Leone, that island lies in the zone between the isoclinals 30° and 53° N., and the advancing edge of the wave would reach it about 18th August of the odd year. The Eclair left Bona Vista on 13th September, and the epidemic did not commence among the inhabitants who had had no communication with her or her people until the 12th October, the usual sickly season there, and it was preceded by heavy rain. It maybe doubted by some when the cases on board the Eclair first assumed the character of yellow fever. I quite agree with the compiler of the Reports on the Health of the Navy, that some of those which appeared when she was at anchor off the Seabar, to the south of Sierra Leone, those of the stoker on the 23rd May, and of Field on 4th June, were not to be distinguished from those that occurred subsequently, in short, were really cases of yellow fever. There is no doubt, too, that at least three cases of this disease proved fatal on shore at Sierra Leone, altogether independent of the Eclair, two of the subjects having not even arrived in the colonyat the time she sailed. There is thus evidence that in the year when fevers were to be expected in that zone, yellow fever appeared in the Eclair, and on shore at Sierra Leone independent of each other, and subsequently, but not before, the wave had reached it, at Bona Vista. So far these may be considered by some as coincidences merely, but on tracing the course of this wave it is found that at Santa Cruz in Teneriffe, in the next zone, an epidemic prevailed in 1846, resembling, if not actually, yellow fever, and the millesimal ratio of mortality among the troops from fever rose in the Ionian Islands from 2-5 in 1845 to 6-8 in 1846; in Malta from 1-1 to 3-0 ; at Gibraltar from 09 to 67 ; and at the last named station one case presented yellowness of conjunctiva and skin, and so much resembled yellow fever that an epidemic was anticipated. In 1847 this wave extended to the British Islands, leading to a great development of febrile disease. These facts leave no doubt that the independent manifestations in the Eclair and at Sierra Leone were connected with the pandemic influence, under which also Bona Vista came the same year, and which was so distinctly manifested at Teneriffe and through the Mediterranean the following year, and in England the subsequent one.

The outbreak of yellow fever in Brazil in the end of 1849, took place under similar circumstances. Rio Janeiro, where it commenced on 28th December, is so situated in the zone between the isoclinals 30° S. and 0°, that the wave would reach it about the middle of October of the odd year, and the epidemic commenced, as is usual in the southern hemisphere, soon after the summer solstice there.

In 1853 a severe epidemic of fever occurred at Monte Video. Opinions were at variance as to whether it was yellow or not; but the possibility of yellow fever arising there was placed beyond doubt by its appearance in 1857. This place lies between the isoclinals 53° S. and 30° and the wave would reach it about 1st November of the even year, and as at Rio Janeiro fever was to be looked for at the commencement of the following, in this case the odd year. I have not the exact date of its appearance in 1853; but in 1857 it commenced in February and continued to the end of May. In continuation of the epidemic of 1853 at Monte Video the severe epidemic at Lima in the beginning of 1854 shows the progress of the same wave. This would pass the isoclinal 30° N. on the 1st January 1855, and in the course of that year there was an extensive epidemic of the febrile affection denominated ” Matlazalhutl” in the southern portion of Mexico. Cholera was common in several islands in the West Indies in 1855, and in the end of the year there was a partial outbreak in Jamaica, and, as seems usual where this disease prevails, fever was little met with, but in 1856, the second year of the wave, there was a pretty severe epidemic of yellow fever in Jamaica and at Havanna. There was a slight epidemic in 1856 at Bermuda, and a few cases at Lisbon, Oporto, and Corunna, but here, as in the West Indies the previous year, cholera was rife in 1856, which seems to have checked the development of the fever, through the first year of the febrific wave at Lisbon, and it was only in 1857, after the disappearance of the cholera, that the yellow fever became epidemic there. This alternation of fever and cholera is frequently met with, the conditions suitable for the development of fever appearing adverse to cholera, and vice versa, those favouring the extension of cholera checking the appearance of fever.

IV. THE CHOLERIFIC WAVE.

An examination of cholera epidemics brings out the fact,

that they, like those of fever, move with regularity from south to north, and that their local manifestations from year to year may be embraced by a succession of waves, which advance at the same rate, and are limited by the same lines of magnetic dip, as have been employed in connection with those of fever. There is this difference between them however, that, on a series of years, the maximum of cholera occurs in any given zone the same year with the minimum of fever there; in other words, that the first year of the cholerific wave coincides with the second of the febrific, and thus the cholerific wave on 1st January in the

[table]

Will leave the isoclinal . . .  [as above]

There are few places, where cholera forms one of the prevalent diseases, for which the records of mortality are available in such a form as to permit of the monthly and annual death rate being defined, as has been done for fever in Jamaica in the former part of this paper; but a table of the deaths at Bombay from February, 1851, to January, 1864, inclusive, which appeared in a paper by Dr. Macpherson in the Medical Times of 23rd November last, gives the necessary details for that place. The sum of the deaths each month, for the fourteen years, is lowest in September, and as the cholerific wave is supposed to overspread the zone between the isoclinals 0° and 30° N. in the odd year, by taking the numbers for the twelve months commencing with September in that for the first year of the wave at Bombay, and similarly those commencing with September in the even one for the second year, their relation to each other is brought out as follows :—

[table]

If these figures be projected as a curve the inflexions are rendered quite distinct, and leave no doubt as to the existence of a wave in connection with cholera as with fever, and of the intensity of cholera coinciding with that portion of the febrific wave when its influence is least. The lowest point in the curve, too, agrees within narrow limits with the interval between the receding and advancing waves, as deduced, either from the actual magnetic dip at Bombay for the mean period, or from actual measurement on the chart. The mean dip at the Bombay Observatory for 1857-58 was 19.2°. And as the wave is supposed to move from the isoclinal 0° to 30° N. in the course of the odd year, it should reach Bombay about the 20th August, while measurement in the chart gives the 6th August as the approximate date.

Cholera is met with in three forms, viz., the epidemic, the sporadic, and the common bilious or English cholera, and there is much diversity of opinion as to the relation these bear to each other. I have met with sporadic cases, within the tropics, which presented every symptom characteristic of the epidemic form of the disease, and many others have had similar experience. I, therefore, believe they were essentially of the same nature as those which when they occur in greater numbers constitute an epidemic. The common or bilious form, though resembling the epidemic in some respects so much as to receive the same name, still differs not only in the character of the intestinal evacuation, but in the absence of the suspension of the function of the kidneys so common in the latter, and, so far, they present much the same affinity to each other that intermittent does to yellow fever. Like these, too, when the epidemic cholera prevails, other places in the same zone, often very distant in longitude, frequently present an unusual number of the sporadic or bilious cases, though far beyond the limits of the epidemic disease, thus indicating that all these forms are influenced by the same general cause. A single illustration may be given.

In 1825 a wave passed to the north of the isoclinal 0°, and the mortality from cholera among the white troops in Ceylon rose to 21.4 per 1000 from 0.6 the previous year. In 1826 when this wave would overspread the zone beyond 30° N. the deaths among the white troops in Bengal rose to 21T per 1000 from 6-7 the preceding year; in Bombay the ratio fell a little, but was still high. Cholera was epidemic in China this year. In the West Indies the ratio of admissions rose from 90 in 1825, to 24.0 per 1000, though with but one death. In Jamaica there was one case only, which proved fatal however, and was the first death from this disease there for ten years. In 1827 the epidemic disease spread beyond the isoclinal 53° N. into Tartary. This year the ratio of admissions in the Ionian Islands, which had been high for several years, continued with little change. At Malta there was an increase, and at Gibraltar a diminution in the admissions. In 1827, too, the second year of the wave, the admissions in Jamaica increased to 16.5 with a death, and in the West Indies they fell to 9.3 with three deaths. In 1828 the cases at Bermuda were 45.6 per 1000, there having been none the previous year, and this year also at Gibraltar the admissions were nearly quadrupled. The admissions in Nova Scotia were 3.1 per 1000 in 1828, and in Canada 6.l, but as in Jamaica and Gibraltar inthesecond year of the wave here, 1829, the ratio rose to 11.2 and 15.4 respectively, with three deaths in Canada. There are numerous other instances of the same description.

According to the theory announced above, the first part of the cholerine wave would overspread the British Islands in the even year, and this is quite in accordance with the facts. The epidemic which commenced in the north of England in the end of 1831, was under the second year of the same wave which had reached Orenburg in August, 1829, and which in 1831 had also caused the disease in Iceland. The epidemic, which commenced in the south of England and Canada in 1832, was under the first year of the following wave. The epidemic of 1834 was experienced at Havanna, and Lisbon and south of Spain, in 1833, and reached England and Canada the following year. The epidemic, which passed northwards through to Russia in 1847, was felt beyond the isoclinal 70° N. in 1848, and became apparent in England late in the year only, as the fever then prevalent declined, but in 1849 it became fully developed. The occurrences of 1853-54 were parallel to those of 1831-32, the first appearance of the disease in the north of England in the former year was under the second year of the wave which had led to the outbreak at St. Petersburg and in northern Russia in 1852, and the epidemic of 1854 was experienced in the south of Europe in 1853. The same explanation applies to the epidemic of 1866 which may here be examined somewhat more in detail.

The first indications of this wave I have met with were at Natal in South Africa, and Mauritius, in 1861. At Mauritzburg in the former, in the end of January or beginning of February, diarrhoea with watery evacuations was prevalent, and one case occurred presenting all the characters of epidemic cholera, with complete collapse. This information I had from Dr. Mann who attended the patient, and who had been familiar with cholera in England. There were six attacks among the troops in Mauritius in the end of 1861, four of which proved fatal, and in 1862 a severe epidemic ensued. This wave would pass the isoclinal 0° on 1st January, 1863, and this year there was a slight increase in the attacks and mortality among the troops in Ceylon, and the ratio of mortality of the previous year was continued among those in the Madras Presidency. There was also a fatal case among the troops in St. Helena. The wave would reach Bombay in the course of August this year. The deaths from cholera there, from September 1862 to August 1863, the second year of the previous wave, and those for the twelve months from September 1863, the first year of that under consideration, were as follow :—

[table]

These figures bring out most distinctly the influence of the advancing wave in increasing the mortality over that of the previous year, and this is obvious in every month, except October and July. The mortality among the white troops in the Bombay Presidency was 2.1 per 1,000 only in 1864, and was confined to the Bombay, Poonah, and Mhow divisions, but among the native population in their vicinity the disease was much more active. In Bengal there was little cholera among the white troops, and it was chiefly met with at Lucknow and Allahabad. In 1865 the deaths in Bombay itself were slightly less numerous than in 1864, but the details for each month are not given, which prevents a full comparison with those under the first year of the wave there; these were, however, 431 in December 1864, and 363 in January 1865, indicating much activity of the causes of the disease at that time. Among the white troops in the Presidency the mortality rose to 159 per 1,000, cholera having appeared in all the military divisions, though to the greatest extent in the Bombay, Mhow, and Northern Divisions, and in the Bengal army the Saugor, Gwalior, and Oude divisions were visited severely. There was, then, an unusual activity of the causes of cholera in the tract of country extending from Bombay north-eastwards to the base of the Himalayas, while there were lesser degrees of the same met with at Poonah on the south-east, and at Hydrabad and Kurachee to the north-west. It was evidently in connection with these occurrences that cholera appeared early in 1865 at Makallah on the Arabian coast, and at Hodeida in the Red Sea south of Jcdda, and subsequently at Mecca among the pilgrims congregated there. All these places, like Hindostan, were under the second year of the •wave, and the outbreak of the disease in the former, contemporaneously with its great aggravation in a portion of the atter, indicates the operation of a general cause quite distinct from those personal or local causes, to which alone it has been attributed. The reason for this cause not having embraced Arabia in its influence in 1864 as well as Bombay, cannot be given with certainty, but there is satisfactory evidence that in that year fever was very prevalent on the west coast of Africa between the isoclinals 0° and 30° N., that it prevailed along the course of the Nile, and especially at Khartoom, and that it was more among the troops, both in the Madras Presidency and in Birmah.than in 1863. It seems probable that that part of Arabia between the same isoclinals was similarly affected, and, indeed, the reports at the time were, that, up to the early months of 1865, low fever was very prevalent at Mecca. It has already been mentioned that the conditions which favour febrile epidemics seem adverse to those of cholera, and this, so far as our information extends at present, seems the most reasonable explanation of Arabia and Egypt having escaped cholera in 1864.

The wave under consideration, according to their regular progress, would pass the isoclinal 53° N. on 1st January, I860. I am not aware of any evidence as to cholera having manifested itself in Tartary this year, but, as all are aware, alter showing itself at Alexandria in June, it soon appeared at many points on the north coast of the Mediterranean, and began to penetrate the various countries where it showed itself, but now, unlike the rapid progress it had made between the isoclinals 30° and 53° N., its advance was gradual and regular, as it seems always to be under the first year of the wave, and at no place in Europe did it commence as an epidemic earlier than the wave would reach it, and though three were small isolated outbreaks near to or beyond the isoclinal 70° N., in the end of 1865, yet the disease did not become epidemic up to, or north of that until 1866, the year when previous experience indicated this might be expected. In America it observed the same law.

The length this communication has reached renders it unadvisable to add farther details; those desirous of these may find them in the original papers to which allusion has already been made.

.

Page 288

OBSERVATIONS ON OUTBREAKS OF CHOLERA IN SHIPS AT SEA.

By KOBERT LAWSON, Esq.,

INSPECTOR-GENERAL OP HOSPITALS, ROYAL AKMY.

[Read June 10th, 1871.]

At the solicitation of Dr. Milroy I have arranged the memoranda in my possession regarding outbreaks of cholera in ships at sea for submission to this Society. In addition to the interest these narratives excite, some conclusions may be drawn from them of the utmost importance in the present state of epidemiology. In investigating such points we have frequently to deal with slight manifestations of disease, which, in the default of a knowledge of their causation, many attribute to chance; but Nature does nothing by chance, and never presents us with a result, however trivial it may appear, which she has not brought about by the action of a sufficient cause; and no one can succeed in explaining her laws who neglects even the slightest indications she presents of their operation.

Most of those present are aware that I have supported the view that the concurrent action of at least three classes of causes is necessary for the development of epidemics— viz.: (1) General causes, one of which I have indicated, in connexion with fever and cholera, by the term Pandemic Wave; (2) those connected with locality, as distinguished from the persons who reside in it; (3) causes connected with persons, as distinguished from those depending on locality. If the latter classes be fully developed, intense disease may be excited under the influence of the general causes; while, if they be less developed, notwithstanding the operation of the general causes, sporadic cases or small groups only may make their appearance, or the inhabitants of certain localities may escape altogether, while those of others in their vicinity (and often mixed up with them in the most extraordinary manner) may display a large amount of sickness.

When examined for a sufficient length of time, and over an adequate space, the course of Pandemic Waves is found to be uniformly from south to north according to a definite law, and their position from year to year can be indicated on a map by lines of equal magnetic dip. This has been done in the map on the wall* for January 1st of each consecutive year. These lines, it will be seen, in some places pursue nearly the same direction as the parallels of latitude; in others, as down the western shores of Europe and Africa, they cross the parallels of latitude at considerable angles. The whole system of isoclinals has a motion to the westward, each portion, however, maintaining nearly the same angle with the parallels of latitude as represented on the map. From this it follows that where the isoclinals pursue nearly the same course as the parallels of latitude, they present little change of latitude on any given meridian for a considerable number of years; but where they are more oblique, as on the west coast of Europe and Africa, their motion to the northward, on any meridian, is so rapid that in a few years it becomes sensible, and requires to be allowed for. This change at London is equal to \\ days per annum in the arrival of the wave, and the same may be employed as far as St. Helena; at the Cape the change amounts to If days per annum. As the isoclinals in the map are their positions in 1840, the corrections named must be applied for the number of years which may have elapsed in any particular case within the limits mentioned. The position of the advancing edge of the wave for any period of the year 1840 may be found by simple proportion from the lines on the map, and this must be corrected in the manner indicated for subsequent years.

It is obvious that if there be a series of waves proceeding from south to north, which can influence the frequency of cholera in communities otherwise favourably circumstanced for its manifestation, we should find, from time to time, that ships passing in the opposite direction experienced one or more outbreaks of cholera in the positions where they run into these waves, and that there should be intervals between them, of greater or less extent, comparatively free from the disease; the same should be experienced when they go from

* See also map in Sanitary Report for the Army for 1866, p. 383, and Epidemiological Transactions, vol iii, p. 216.

south to north, provided only they proceed more rapidly than the wave; while, if their course be nearly east or west, they may continue from commencement to end of voyage in the same waves. Having premised these explanations, the details of various outbreaks may now be given, and it will be seen how far they support this view.

The first case to which I have to draw your attention is that of H.M.’s ship Apollo, which carried the 59th Regiment from Cork to Hong-Kong in 1849. The first account of the occurrences in this ship, to which I had access, was that by Dr. Bryson, late Director-General of the Naval Medical Department, in a small volume “On the Infectious Origin and Propagation of Cholera,” published in 1851. I have recently been so fortunate as to meet the medical officer who was in charge of the troops in the Apollo—Dr. Fraser, 10th Hussars—and have been favoured with the perusal of his journal and reports, which afford many details not given in Dr. Bryson’s account.

The Apollo was a frigate-built ship, having beneath the upper or weather deck a gun deck with ports on each side, and below this the orlop, which had small side scuttles, which could be opened in fine weather only. The gun deck was occupied by the officers abaft, and by the crew on the starboard side forward, and a portion of the troops on the port side; the remainder were on the orlop. The latter, of course, could not be so efficiently ventilated as the former. The troops, including women and children, amounting to 593 persons, embarked on June 12th, and the ship sailed on the 1 7th. Cholera had prevailed in Cork and its vicinity previous to the troops going on board, but there had been none in the ship herself up to this time. Subsequently the course of the disease was as follows: (See opposite page.)

The first case of cholera occurred in a soldier who had had diarrhoea for some days, who on the morning of June 18th went on deck, after getting out of his hammock much heated, and placed himself under a water-tap, and let the water run over his body. Collapse ensued immediately; there were slight cramps with the characteristic evacuations, and he died in seven hours. No other case presented itself until nine days afterwards, from which they continued to crop up until July 10th. On the 14th and 15th there was heavy rain, and another case occurred on the 16th; the 17th was also rainy, followed by a case on the 18th. From the 19th to the 22nd inclusive the ship seems to have been becalmed, as her position altered but a few miles daily, and

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during that period there were twelve attacks, including the quarter-master of the 59th (the only officer attacked) and seven of the crew (the first among them), and six deaths. On the 23rd there were two attacks, including one of the crew (the last of these affected). The ship seems to have got a breeze on the afternoon of the 22nd, and in the course of the 23rd to have met the S.B. trade, and for some days there was another lull in the attacks, but on the 29th and 30th, while in the S.E. trade, there were five attacks and four deaths, and on August 6th and 12 th another two, after she had passed out of the trade altogether.

During the prevalence of the malignant disease Dr. Fraser states diarrhoea and colic prevailed to an unusual extent, and appeared to keep pace with it, increasing as it increased, and disappearing generally with its disappearance. The diarrhoea was generally of such an aggravated form that he thought many of the cases, if not most, would have been returned during an epidemic in England as true Asiatic cholera, presenting as they did profuse vomiting and purging, great prostration, remarkable sinking of the features, and even slight cramps occasionally; but he carefully refrained from designating any case cholera in which the characteristic rice-water evacuations were not present, and the natural secretions suppressed.

The appearance of the men soon after embarkation attracted the attention of the officers on board, both naval and military. Dr. Fraser describes them as attenuated and without spirit, their eyes sunk in their heads. They were on two-thirds allowance, as was customary at that time. Preserved meat was served out every fourth day; the contents of many of the cases were found putrid, and great quantities of it were thrown overboard on every occasion on which it was issued. The men had an excessive dislike to the preserved meat, and were fully persuaded it was the chief cause of the disease among them. They also had a strong aversion to the cocoa issued for breakfast, and, on representation, tea was substituted for that, the issue of preserved meat stopped, and oatmeal-gruel given in the evening, from about the middle of July to September 7th.

Whether the issue of preserved meat to the crew was suspended during this period is not mentioned, but Dr. Fraser has since informed me he thinks it was not.

It will be remarked that, though cholera had been in the ship for a month previously, none of the crew were attacked before July 19th. There were two wide tubes on each side for allowing heated air to escape from the orlop, but as they terminated on the gun deck, instead of being carried into the open air, they merely relieved the lower deck of impure air by diffusing it on that above. Dr. Bryson states that these tubes were not opened untilJuly 17th, two days before the occurrence of the first cases among the crew, and he adds, “the greater number of the cases on this deck occurred among the men belonging to the messes close to the apertures of the tubes, or to the main hatchway, by which the impure air also escaped;” and he concludes that the disease was communicated from the lower deck to that above by means of this air. Dr. Fraser had made a diagram showing the relative position of the various messes, and of these tubes and the hatchways; and those, members of which were attacked, were also indicated. From this it appears the messes were numbered from 1 to 8, No. 1 being the foremost, No. 8 the aftermost. There was a gun between 1 and 2, another between 2 and 3, and a third between 3 and 4. One of the tubes was between the second gun and the third mess, the other between Nos. 4 and 5 messes, while Nos. 4 and 8 messes were about equidistant from the main hatchway, and 5, 6, and 7, of course, nearer it; No. 2 mess also was directly abreast the fore hatchway. Now, the cases presented themselves as follow :—

In No. 1 mess, away from hatchway and tubes—one case on 19th, one on 23rd.

In No. 3 mess, beside a tube, but away from a hatchway —one case on 19th, one on 20th, one on 21st.

In No. 8 mess, in vicinity of main hatchway, away from a tube—one case on 19th, two on 20th.

So that No. 2, near a hatchway, Nos. 4 and 5, with a tube between them, and as near the main hatchway as 8, and Nos. 6 and 7, still nearer it, altogether escaped. It is obvious, therefore, that mere vicinity to the outlets from the lower deck, and presumably to the emanations from it, could not have been the active cause of these attacks among the crew, though, no doubt, during the close, calm weather existing from the 19th to the 22nd, the vitiated air from the lower deck would be less rapidly diffused, and, so far, more injurious, than either before or after, when there was a good breeze. If, as Dr. Fraser thinks, the crew continued to use the preserved meat, it is possible that some more tainted than the rest was consumed by the messes which suffered.

The authorities at Rio Janeiro would not allow the Apollo to communicate with the shore, but directed her to proceed to the Uha Grande, about sixty miles to the westward, where her crew and passengers were disembarked, and the holds cleared out. These were found clean, dry, and free from offensive effluvia, andnone of the persons engaged in the work were attacked, nor, indeed, did any more cases of cholera occur during the remainder of the voyage. After leaving the Ilha Grande, on September 7th, the Apollo called at the Cape, where she seems to have taken in water, at least; subsequently she touched at Booroo, where more water was taken on board, and immediately after its employment was commenced bowel complaints became frequent, and there were more admissions from this form of disease in January than in the four previous months. On February 1st the use of the Booroo water was discontinued, and some which had been obtained at the Cape substituted, and the number of cases of diarrhoea at once diminished. Though not connected with the cholera in the Apollo, this fact in the narrative of her voyage was too significant to be omitted.

The next case to which I will direct the attention of the Society was that of the Renown, which took the 1st Battalion 9th Regiment from Gibraltar to the Cape in 18ii5. The Renown, a fine ship of 1293 tons, with a crew of fifty-two persons, sailed from Kingston for Gibraltar, with troops on board, on August 3rd, 1865, and arrived on 17th, and there does not seem to have been any bowel complaint among them or the crew during the voyage. The head-quarters 1st Battalion 9th Regiment, including sixteen officers, 353 men, twenty-eight women, and sixty-five children, embarked in this vessel on August 21st, part at 6.15 a.m., and the remainder at 5 p.m. The men were in five companies, designated A, B, D, F, and K. There was a single berth deck extending the whole length of the vessel, which was extremely well ventilated with side scuttles, stern lights,and shafts leading to the open air above the upper deck. The hospital, as is now the practice, occupied a part of the port side abreast the main hatchway. The companies were berthed as follows :—On the starboard side, forward, was A, followed by F, which occupied the space abreast the main hatchway, and farther aft were the band and drums. On the port side, forward, was B Company, followed by K, which occupied the space up to the hospital bulkhead; D Company was in the centre of the vessel in front of the main hatchway, between K and part of F. The women and children were in the alter part of the deck.

On the morning of August 22nd, a man of F Company, who had embarked on the morning of the 21st, and been employed during the day in assisting to get the baggage on board, was attacked with cholera; he was landed immediately, and died in a few hours. Though the disease had been at Gibraltar for a month previously, no case had occurred in the 9th Regiment, nor in the barracks from which they came, up to the time of their embarkation, and as no fresh case occurred up to the evening of the 23rd the ship then sailed for the Cape, and everything went on well for several days. On the 29th a young child had an attack of diarrhoea, from which it recovered by the 31st. On the 30th another child was affected with diarrhoea, but was well by September 3rd. From this date the attacks became more numerous, as indicated in the following table :—

[graphic][table]

Subsequent to September 20th no one was attacked with bowel complaint or cholera, and there was no death after that date. The ship reached the Cape on October 9th.

The provisions on board the Renown were all of excellent quality. A quantity of water had been taken on board at London, and some at Gibraltar, which was stowed partly in casks and partly in tanks; and though that in the casks was somewhat coloured by them, yet it was considered good. There was a distilling apparatus on board capable of making 500 gallons of fresh water daily, and, from the time of the appearance of the cholera, water from this only was employed for cooking and drinking. The cargo consisted of a general assortment of goods for the Indian market, with iron, and shingle mixed with sand, for ballast; under and around the main hatchway there was a quantity of the latter, which, when I was on board the ship in Algoa Bay in November, was damp, but did not present any trace of mud mixed with the sand. Unpleasant odours from the hold were not complained of during the voyage. After cholera appeared the people were kept as much as possible on the upper deck during the day, and every means employed for ventilating the berth deck as freely as possible, and, as the weather was fine throughout, all the ventilating apertures were constantly open. But for the care taken with these points many more cases might have occurred.

As regards the immediate cause of the cases in the Renown the following facts are material:—It will be remembered that a man of F Company, which was berthed alongside the main hatchway, was attacked the morning after he embarked, and sent on shore at once. The next cases were those of another man of the same company and of a child who was accommodated in the women’s berth at one side, but abreast a small scuttle which led down to the after hold, which was occasionally open. This was the child of a sergeant of F Company, who, with his wife and another child, had been attacked with dysentery on September 3. The attacks and deaths occurred in the different companies, and among the women, children, and crew, as below :—

[table]

Bearing in mind the position of the different companies, and of the women and children in the ship, and the fact that the first case in the regiment and ship was a man of F Company, which subsequently suffered most, and that the others were affected nearly in proportion to their proximity to the hatchways, it is pretty clear that emanations from the hold were instrumental in developing the disease. The crew were all berthed in the poop or forecastle, which did not communicate with the hold. Of these, the surgeon, a man of broken-down constitution, and one seaman, whose duties required him to be frequently near the hatchway, or in the hold, were the only persons attacked with cholera, both of whom died. To complete the history it may be added that the men sick of cholera were treated in the hospital, the women and children in the women’s berth. The bodies of those who died were removed on deck at once, and buried soon after, and their bedding and clothing thrown overboard. The bedding and clothing of those who recovered were freely exposed to the air for some time before being used again.

* Including the first case at Gibraltar.

The Renown was placed in quarantine on her arrival at Cape Town, and a few days after left for Saldana Bay, where the troops were disembarked, and the vessel thoroughly fumigated and whitewashed, and the bedding used by the troops destroyed. Towards the end of October she proceeded to Algoa Bay, where she arrived on November 1st, still in quarantine, and anchored three miles off Port Elizabeth. There had been no case of cholera or bowel complaint among the crew since the troops disembarked. On November 8th she was admitted to pratique, and on the 9th the head-quarters of the 96th Regiment embarked, and the vessel sailed the same afternoon for Bombay. On November 12th one of the 96th, who had had slight diarrhoea for some days previous to embarkation, was attacked with vomiting and purging, the evacuations being like rice-water, but being seen to immediately, collapse did not ensue. The man slept on the port side, near one of the hatchways, a place clean and well ventilated. There had been one case of a similar nature, but with some collapse, on shore at Port Elizabeth on October 30th in a civilian.

In 1866 two ships left the Thames for India with troops on board, in both of which cholera appeared, and presented some features of interest. The details concerning them are not so complete as those given above, but what I have been able to obtain from the official reports of the medical officers, and from the copies of the logs at the office of the Registrar-General of Seamen, is given below.

The first of these, the Windsor Castle, was a fine roomy vessel of 1,074 tons, with a single troop deck, extending her full length, 173 feet long, 33 wide, and 7 high, and the ventilation was fully secured by 8 deck tubes, 39 side scuttles, 3 stern ports, hatches, and windsails. There was a limited cargo of railway iron, chiefly for the purpose of ballasting the vessel. The provisions issued during the voyage were good. On the 11th July 6 officers, 351 noncommissioned officers and men, 35 women, and 35 children embarked at Gravesend, and the ship sailed on the 12th. An artilleryman, a strong healthy young man, was sent on board on the 11th from the cells, where he had been confined; he drank three or four pints of porter before embarking, and the same evening complained of general malaise and diarrhoea. Early on the morning of the 12th he was attacked with cramps in the legs and stomach, and vomiting. The case yielded to ordinary treatment, and on the 13th he was convalescent. The weather continued fine, and the ship cleared the Channel on 17th July. Cases of diarrhoea had presented themselves every day since sailing, but on the 22nd they increased in number, and did not entirely cease until she got into the cool weather, about 30° south. The attacks of, and deaths from cholera, with the positions of the ship at the time, as far as I have been able to procure them, were as follow:—

[table][merged small]

Two days after the last case, a child, aged 14 months, died of mesenteric disease, subsequent to which sickness disappeared, and the ship arrived at Kurrachee on 25th October, all on board in excellent health.

The medical officer in charge, Dr. Hanrahan, Staff-Assistant Surgeon, seems to have adopted the means recommended for the prevention of the disease very carefully, yet it was not got rid of entirely until the ship had passed the Cape of Good Hope. Dr. Hanrahan says, “the sanitary measures that I adopted were as follows: On the first appearance of the disease T had the latrines thoroughly flushed out every tivo hours, and sprinkled with chloride of lime. I changed the water, using no other but distilled, but no good result followed. I made use of fumigations between decks, using nitrous acid fumes. The lower deck was well scraped, scrubbed, and sprinkled with chloride of zinc and lime every day, great attention was paid to ventilation, the men, women, and children were kept on deck as much as possible. All the clothes and bedding belonging to those that died were thrown overboard. The berths were well scrubbed and washed with chloride of lime. I inspected the men daily, and kept the name of the disease secret. Amusements were encouraged as much as possible, such as dancing, singing, &c”

Dr. Hanrahan also states, ” the diarrhoea seemed to me of two kinds; one had a clear red tongue, in the other the tongue was loaded with a white fur. All complained of some pain or uneasiness at the epigastrium, and a great intolerance of any kind of food (with some discolouration of countenance); stools watery.” “Almost all the women and children were more or less affected with the diarrhoea.5′

The second vessel alluded to above was the Lord Warden, which left Gravesend on 15th September for Portsmouth, and sailed from that on 23rd, with 13 officers, 293 non-commissioned officers and men, 32 women, and 29 children on board, besides the crew and somo other passengers. On 25th September the first case of cholera presented itself, which recovered; on the 26th there was another, which died. Up to the 7th October a few cases of diarrhoea occurred, when cholera again appeared. During the epidemic 14 cases were met with among the troops (12 men and 2 children), of whom 8 died; two passengers died. The crew were not affected. Neither the names of those attacked nor the dates are given, but the positions of the ship on the day of each death were as under :—(See next page.)

There were five more attacks subsequent to the 8th October, the dates of which are not given

[table]

In 1867 H.M.S. Jumna, one of the new Indian steam troop-ships, was on her passage outwards. She had a number of military officers on board, but no troops. On 17th July, four days after leaving St. Vincent, one of the Cape de Verde Islands, one case of malignant cholera and six of choleraic diarrhoea occurred among the crew, and the latter continued to present themselves until the 27th, by which time 46 had been entered on the sick-list, besides some 10 or 1 2 milder, which were not. The ship’s position at noon on 17th was lat. 6° 35′ N., long. 15° 46′ W., and on 27th she was in lat. 19° 37′ S., long. 5° 27′ W. Some fresh beef, obtained in England thirteen days before, and brought out in the ice-house, was issued to the crew on the 17th; the marines, who used the beef, suffered more than the rest of the crew, while the warrant officers, who refused it, escaped. One of the military officers had a severe attack of choleraic diarrhoea. There was no cholera at St. Vincent while the Jumna was there. Besides the beef, it was supposed that the fresh bread made on board was sour, and its issue was stopped and biscuit substituted. These facts are principally from the Report on the Health of the Navy for 1867; the positions of the Jumna were communicated by Dr. Mackay.

The ship Newcastle, from India to England, with some detachments of troops on board, sailed from Cape Town for St. Helena on the evening of 2nd April, 1866. About 4 a.m. on the morning of the 8th a soldier was seized with vomiting and purging, the evacuations like rice-water, violent cramps, intense thirst, and soon became completely collapsed. He recovered in a few days. The ship arrived at St. Helena on the morning of the 12th April. There had not been any cholera in this ship since she left India on her home voyage.

There have been numerous outbreaks of cholera in vessels proceeding from Indian ports to the southward; but, unfortunately, the details as to the ships’ positions and the dates of attacks have not been given, and the full significance of these facts remains in abeyance. I have been able to collect a few, in which these particulars are available to some extent, which will permit of their being referred to here with advantage.

The first to be mentioned, noticed by Dr. Macpherson in his work on The Cholera in its Home, p. 25, was in the Sultany, which left Calcutta on February 10th, 1854, with a crew of 80 men and with 375 emigrants. They had no cholera going down the river; but a fortnight after leaving the Sandheads, or on February 29th, it broke out and thirty of the passengers died of it. The ship reached Mauritius on 24th March. Unfortunately, the ship’s position on the appearance of the cholera is not given; but the resemblance of the case to others to be mentioned immediately deserves attention.

In the year 1859 the Peninsular and Oriental Company’s steamship Oriental left Bombay for Mauritius with a portion of the 61st Regiment, which, including officers, men, women, and children, numbered 588. An outbreak of cholera occurred, which led to her touching at Galle, in Ceylon. The troops embarked on 29th June, and the vessel sailed at 2.20 p.m. the same day. The men were well provided for in every respect, save that they were rather crowded and without berths or hammocks, and a considerable portion were kept on the upper deck, where they had to sleep. They were supplied with new. blankets of good quality. The first, and indeed most of the cases, occurred among those who slept on the upper deck, which was perfectly ventilated. At the time the Oriental sailed. cholera was prevailing at Bombay. There is no account of the date of the attacks, but the deaths, with the ship’s approximate latitude, occurred as follow:—

Jnue 30, lat. about 17° N., 1 man died from cholera at 9 a.m. July 1, „ 14£° „ 1 soldier died from do. 7 a.m.

„ 2, „ 12° „ 3 soldiers died from do.

„ 3, „ 9J° ,, 1 woman died, said to be from

sea sickness.

„ 4, „ 7° „ 2 soldiers died from cholera.

„ 5, anchored at Galle at 3.45 p.m., no death this day.

„ 6, at Galle 3 soldiers died of cholera.

„ 11, Do. 1 soldier died of cholera.

The Oriental left Galle on 14th July, and arrived at Mauritius on 28th, no other case of cholera having presented itself.

The next case to which I will refer is that of the Gertrude, which left Calcutta for England in May, 1859. This case has been mentioned in Dr. Murray’s paper on the treatment of cholera, published by order of the Government of India at Calcutta in 1869, Appendix II, p. 18. I have also seen the official report furnished by the military medical officer on board to the Director-General Army Medical Department, and have examined the official log of the ship deposited with the Registrar-General of Seamen. Each account differs from the others in some particulars. That given below has been drawn up so as to include every specific fact connected with cholera mentioned in any of them.

The Gertrude sailed from Calcutta on 21st May with 120 military invalids on board, besides some other passengers and her crew, and on the 27th got out to sea. A passenger died of disease of the heart on 9th June, in lat. 6° 44′ N., long. 87° 35′ E. Some cases of dysentery and diarrhoea seem to have occurred after sailing. The attacks of cholera, with the ship’s position at the time of death, are given below; the others are estimated.

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The next ship in point of time was the Queen of the North, of 840 tons, with a good, well-ventilated troop-deck. She had in cargo 340 tons lintseed in bags, and 150 tons bloodstone, with two feet of clean granite under these for ballast. She made very little water, and the bilge was said not to have been offensive at any time; but occasionally a disagreeable odour from the hold was perceived. All along tinder the upper deck the timbers were exposed, which would allow emanations from the hold being diffused on the troop-deck. The provisions were good; but the water, which had been obtained at Bombay, was always observed to become opaline after exposure to the air for a little. On 2lst January, 1864, 272 persons, consisting of officers, some expired men, invalids, women, and children, embarked in this vessel at Bombay, and her crew numbered 27. She sailed for England the following day. Several of the invalids and women and children had suffered from bowel complaints previous to embarkation. One woman, while under treatment for diarrhoea, was attacked on the evening of the 24th with vomiting and purging, with a disposition to collapse, and died the following eyening; but the medical officer in charge hesitated to call the case cholera. Two other cases, with collapse, but without cramps, and with bilious stools, occurred on the 28th and 29th January; both recovered. The first unequivocal case of cholera, in the surgeon’s opinion, appeared on 1st February, and proved fatal the same day. The ship’s position, with the state of the weather and the number of attacks each day while the outbreak lasted, were as follow :—

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There was no attack after the 15th, and the last death was on the 19th. Altogether, from the 8th to the 15th, there were 37 attacks, of which 24 proved fatal. Diarrhoea was very common, both among the passengers and crew, from about the 5th February; but I was unable to obtain the names or numbers of persons attacked. The cases of either disease did not come from any particular part of the troop-deck, but were diffused all over it. The crew, who lived in the forecastle, which had no communication with the hold, had no cholera; but the chief officer, who used to drink large quantities of water, was attacked and died.

The Salamanca had been fitted out at Bombay for the conveyance of a portion of the 89 th Regiment from Kurrachee to England. She took with her from Bombay 1 officer, 43 non-commissioned officers and men, and after some weeks’ delay at Kurrachee, received on board there 8 officers, 254 non-commissioned officers and men, 7 women, and 15 children, and went to sea on 7th May, 1865. Cholera had been prevalent among the native population at Kurrachee for some time, and a few cases had presented themselves among the troops. Care was taken, therefore, to see all the people embarked were free from it, and one sergeant having lately suffered from it was left behind with his family. There was, however, a case of sharp choleraic diarrhoea on 7th in a man who had embarked at Kurrachee and was suffering from sea sickness, and on 9th another, also suffering from sea sickness since embarkation, was attacked with cholera. The subsequent course of the disease is given below:—

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Six deaths occurred in all from cholera. The man attacked on the 9th was treated in the hospital. Immediately after death the body was stripped and placed in a boat to leeward until buried, and the clothes and bedding thrown overboard, the berth scraped and sprinkled with

Sir W. Burnett’s solution (chloride of zinc). The subsequent cases, as well as those of diarrhoea, were treated on the forecastle, the evacuations thrown overboard as soon as passed, and chloride of zinc freely thrown down the latrines. The issue of porter was stopped on the 12 th, and rum given instead. There was no attack of cholera after the 14th; but the frequency of intermittent subsequent to the rain of the 1 6th and 17th is worthy of remark.

The last instance I will bring forward is that of the Durham, from Calcutta to England, in 1866. She received 13 officers, 422 non-commissioned officers and men, 15 women, and 25 children at Calcutta on February 24th, and seems to have sailed the following day. She must have left the land on 26th or 27th, as her latitude on 1st March was 17° 20′ N. The ship’s provisions were good, the ventilation sufficient, and the materials for fumigation ample. The first case of cholera appeared on 9th March; the course of the disease subsequently was as below :—

[table]

The medical officer reported, “the intense heat between decks was so great that, at my suggestion, nearly half the men slept on deck. It is worthy of notice none of these men were attacked with cholera. I had frequent parades for the detection of diarrhoea amongst the troops. Salt pork as a ration and limejuice were temporarily stopped, and every other sanitary measure that could be carried out was recommended and adopted.”

If, now, we analyse these details, we find that, in the Atlantic, the Apollo in 1849, the Renown in 1865, the Windsor Castle and Lord Warden in 1866, left places where cholera was prevailing when they sailed, and all of them immediately previous to, or soon after, going to sea, had one or more cases of this disease on board. After being at sea for some time with few or no attacks, these again became more numerous, and after a while ceased. In the Apollo

Vol. m. x

and Renown there was a second outbreak; and in the Jumna, in 1867, which had not come from a place where the disease existed, her first case was experienced at sea, in nearly the same latitude. The Windsor Castle, again, had another case after she was far to the east of the Cape of Good Hope. In the Indian Ocean, the Gertrude and Oriental in 1859, the Queen of the North in 1864, the Salamanca in 1865, and the Durham in 1866, all left places where cholera existed at the time, and all of them experienced attacks at sea at varying intervals after leaving the land. The Gertrude even had two deaths to the south of Mauritius.

We can now examine whether the positions in which these ships experienced their outbreaks agree with those which from other data I have assigned to the cholerific waves proceeding from the southward.

When the Apollo left Cork, Ireland was under the epidemic of that year, though the second year of the wave there. The next wave, on June 27th, would be met with in latitude 37|° N., on the meridian of 14£° W.; and on that day this ship, in latitude 35° 21′, had the first case for nine days, and an outbreak commenced which lasted till July 23rd, after which there was a respite for six days. The following wave, on the meridian of 33° W., would be met with in latitude 5° S., on July 27th; and it was after passing this point that the Apollo had her second outbreak, commencing on July 29th.

The JRenown sailed from Gibraltar when the Mediterranean was under the first year of the wave. After the first case, she had no other until she was at 12° N., when the disease commenced again, and continued until she reached 2£° N., when it ceased, and did not recur until three days after, when she got into 4J° S. Having a strong trade at this time, her daily runs were much greater than those of the Apollo. The Renown would enter the advancing wave on September 15th, when its position on the meridian of 30° W. was about 1\° S.

The Windsor Castle and Lord Warden both sailed when England was under the influence of the first year of the wave of the epidemic of 1866. In their progress south, both encountered a fresh wave a little to the north of the Cape de Verd Islands. On August 6th, when the former was in this vicinity, the wave on the meridian of 22° W. would be at 18° N.; and on September 15th, when the other was passing, the wave on the meridian of 20° W., would be at 20J° N. The outbreak in the Windsor Castle commenced about 10° N., within the limit here given for the advancing wave, and that in the Lord Warden in 28° N., only a short distance outside its estimated position. In the Windsor Castle the last attack was on September 15th, when she was in 37° 20′ S. and 38° 41′ E., the preceding case having occurred twenty-six days before. At this point she was within the influence of another wave, which, on the meridian of 39° B. on that date, would have reached 31° S., and of which distinct indications were soon after experienced all along South Africa.

The case of the Jumna differs from those of the other ships already mentioned, in that no cholera existed in England when she left, nor at St. Vincent when she touched there; and the first indication of cholera occurred in her at sea. On July 1 7th, when the attack commenced, the estimated position of the advancing wave on the meridian of 14|° W. was at 3° N., little more than 200 miles from her place at noon on that day, and choleraic diarrhoea continued to manifest itself until she reached 19|° S., ten days after. It will here be observed that the Apollo, Renown, and Jumna, in years with odd numbers, met these waves in nearly the same latitude, while the Windsor Castle and Lord Warden, in even years, met with them considerably further to the northward.

In the Indian Ocean, the Gertrude, soon after leaving Calcutta, encountered a wave on June 1st at 15° N., near the meridian of 90° E., and the first few cases, up to June 16th, occurred in this. The next case manifested itself on the 20th in 11° S., the estimated position of the approaching wave at that timebeing 13 S. on the meridian of 80° E., or 120 miles only from her actual place. Under this wave, too, she had two cases to the south of Mauritius. The Oriental encountered the same wave on June 30th in about 18° N., and in her the outbreak commenced at once.

When the Queen of the North left Bombay cholera was pretty active there, and she showed traces of it on her way south. On February 7th she reached the estimated position of an advancing wave in 4° S. and 80° E., and on the following day an outbreak of extreme violence commenced, there having been 37 attacks among 298 persons on board in the next seven days, of whom 24 died. The following year the Salamanca left Kurrachee, where cholera was prevailing at the time, and she had some cases immediately after. On May 10th she would meet the same wave, mentioned above in connection with the Queen of the North, in 16° N., and the following day she experienced a considerable increase in the number of cases and of choleraic diarrhoea.

The Durham had left the land about ten days before the first case presented itself, and the second occurred ten days later, when on the equator, and five other cases proved fatal in the. next twelve days. There were three cases, however, which recovered, and a large number of choleraic diarrhoea during this period, the dates of which occurrences are not available, so that the exact point where the outbreak became intensified cannot be made out satisfactorily. The estimated position of the wave the Durham encountered about this time was on March 21st, in latitude 3f° S. on the meridian of 90° B.

The manifestations of cholera under these different waves were not confined to the ships mentioned in connection with them, but many traces of their influence were found elsewhere as well. The Gertrude, though in the same wave as the Oriental, had her first case much nearer to the line, and the activity of the causes of the disease on shore corresponded with this, as both in Ceylon and Madras it was much less severe than a few months before, while on the west coast of Hindostan, and still more on the east coast of Africa, it was then very prevalent. As already stated, the Gertrude had two cases to the south of Mauritius. There was a considerable outbreak in 1859 at Mauritius; there were also some indications of cholera in the Cape Colony, and a severe epidemic at Zanzibar, commencing in December, clearly showing that the cholerific influences were felt over a very large area, and among communities quite independent of each other.

The series of outbreaks, of which that in the Queen of the North to the south of the line in 1864 was the earliest, was a very striking one. The epidemic, as shown above, was followed by that of the Salamanca in latitude 14° N. in May the following year. The same year a very severe epidemic ravaged the district on the west coast of Hindostan from 10° to 12° N., which commenced in May. In the same latitude, on the west of the Arabian Gulf, H.M.S. Penguin captured some slave-dhows with cholera on board, and one of her people was attacked in April and another in May. The disease also, commenced at Aden in May, and subsequently extended into Laheg. At this time, too, it was prevalent nearly as far south as Zanzibar. To the west of Africa, in the middle of the Atlantic, the Renown met the same wave on September 16th in 4£° S., and in 1866 the Windsor Castle and the Lord Warden ran into it to the north of the Cape de Verd Islands. In the course of 1866, too, cholera prevailed under its influence in Abyssinia, at Mecca, and along the Euphrates as far as Turkistan; and in 1867 there was a severe outbreak, extending from Constantinople, through Southern Europe, Sicily, and Malta, embracing Tripoli, Tunis, and Algiers in Northern Africa. The influence of this wave was experienced in England and the North of France in 1868 in a manner sufficiently decided to leave no doubt of its presence, though the form of the disease was mostly simple cholera, and the resulting mortality was not so greatly increased as to entitle it to be designated an epidemic.

In like manner, the case in the Newcastle and the outbreak in the Jumna can be traced from the Cape. In February, 1865, there was a considerable number of severe cases of sporadic or common cholera, and a good deal of choleraic diarrhoea, at Cape-Town.- In October, there was a case of ordinary cholera at Port Elizabeth, and another in the Renown at sea on November 12th. There were also several cases in coolie ships in quarantine at Mauritius in

1865, and two cases on shore in September. In April,

1866, the Newcastle had one case midway between Cape Town and St. Helena, and in the end of 1866, cholera became epidemic at Rio Janeiro. In 1867 H.M.S. Jumna had an outbreak in the eastern part of the Atlantic, near the African coast, and in 1868 the further progress of this wave was indicated by the epidemic which commenced at St. Louis on the Senegal in the beginning of December.

The last wave the facts given above embrace is that . which was first indicated by the death of the seaman of the Windsor Castle, to the south-eastward of the Cape, in September, 1866. In October of that year, a lady, who had not been out of the colony, died in Cape Town of cholera, and in December, choleraic diarrhoea suddenly showed itself all over Maritzburg, in Natal; and in February, 1867, choleraic diarrhoea became very common at Cape Town and Port Elizabeth. In January, 1868, cholera appeared at Buenos Ayres and Monte Video as an epidemic, showing, as in the instances previously given, that the cholerific influences were very widely spread, and were progressive, and that the aggravation of the disease in ships was merely an indication of a cause or series of causes of general operation.

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