William Aitkins wrote his book during a period of drastic change in medical and epidemiologic history,  The theory for diseases was converting from a set of theories based primarily on miasma concepts to a theory based more upon William Farr’s propositions about the zymotic theory for diseases.  The zymotic theory in turn facilitated the visualization needed for physicians to imagine there to be multiple, very different causes for disease, of both a visible and invisible nature.

This change in theoretical focus is akin to the early 18th century movement in which William Cullen took the classical humoural theory so popular the centuries before and turned the attention of physicians to the organ fed by our blood, a proposal that came to be known as the solidist theory of disease, which focused on the individual organs and their independent processes.  Countering Cullen’s focus on solids was Brunonianism, the focus on nervous excitement as a source for disease onset, an energy based philosophy that partially satisfied the curiosities of believers in the “vital spark” and the roles of various forms of natural electricity used to generate that vital spark, make the nerve and muscle work, and give temporary life back to certain parts of the body removed from the individual animal or human as a whole.

Aitken paid minimal attention to physiology and anatomy in this portion of his review of diseases.  His purpose here was to lead to his later review of Farr’s nosology of disease in considerable detail, almost without change.

This section of the book by Aitkens provides us with some insights into his interpretation of the recent naturalist’s theory for disease that prevailed between about 1790 and the date of his book.  Like another writer of the various forms of miasm, German medical geographer Canstadt, Aitkens had a philosophy to express about the different forms and presentations of miasm that nature had to display for us.

This chapter has preceding it the following basic classes of disease that Aitkens built upon in his earlier writings.  These classes are reviewed in detail on another page.

Under the class of Zymotic diseases the following orders are to be distinguished and described, namely,—

Order 1. Miasmatic Diseases—Miasmatici

Order 2. Enthetic Diseases—Enthetici.

Order 3. Dietic Diseases—Dietici.

Order 4-. Parasitic Diseases—Parasitici.

With this philosophy Aitken takes the miasma concepts for certain diseases and replaces them with another traditional terminology and philosophy–the notion of sickness being due to “poisons”.  The poison Aitken speaks about is not the chemical version of poison which we naturally imagine in our mind today.  Malaria was linked to poisons, and that term “malaria” was also not at all like the malaria we visualize today.   The “malaria” Aitken refers to is that theoretical substance floating about that i toxic to our body, and capable of making us ill by poisoning our natural processes.  Poison contrasts with miasma in that it is more physical, less ambiguous in form and behavior, and at times more isolated in the people and even more predictable at times.  The influences of certain poisons can sometimes even be stopped by the use of another poison.  

These poisons are emitted by people, animals, products, not injected into us like venoms or toxic oils like from poison ivy.  Those poisons are placed in another class.  Aitkin’s pathological miasmatic order of zymotic diseases that he considered “poisons” is a hybridization of past and future concepts for disease, the pathway taken from being totally dependent upon miasma theory to one more accepting of zymosis and zymotic disease definitions.  Once described and understood, these concepts can then be used to explain the events that happen with onset and diffusion of endemic diseases versus epidemic diseases–the topic of the second chpater reviewed on this page, and the third chapter in this part of Aitken’s book.

This page and writing relate back to other pages at this site, but especially Lawson’s descriptions of epidemics, their cyclical oscillation, and the relationship of this behavior to  the earth’s magnetic field fluctuations, a very controversial philosophy for the time which would ultimately be more of a popular culture derived fad amongst physicians, than a fully accepted new way to describe disease patterns considered completely truthful and not at all speculative.

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THE SOURCES OF MIASMATIC DISEASES. 203

 

CHAPTER II.

PATHOLOGY OF THE MIASMATIC ORDER OF ZYMOTIC DISEASES.

The diseases to be described under this order acknowledge at least three sources or modes of origin; while they are all mainly propagated, disseminated, communicated, or diffused through the agency of contaminated persons, food, water, or other agents, or through infected air. The poisons, miasms, gases, germs, active principles, or morbific agents may be arranged under three classes, namely,

1st. Palludal malarious poison;

2nd. Animal malaria poison;

3rd. Specific disease poisons.

The diseases they engender are attended by a febrile state which may assume various forms or types.

Paludal Malarious Poison-—This poison arises from marshy land in particular conditions, such as decomposition under the influence of partial moisture, and of heat above 60° Fahr. If the land is perfectly dry or perfectly flooded the poison is not generated. It is a material poison. It may be wafted along with the wind, and so induce fever at a distance from the place where the poison is generated. It may also be intercepted by a belt of trees. It appears to be most intense near the surface of the ground. The diseases usually attributed to this endemic source, and which were formerly so destructive, have almost disappeared from this country. The reason of this may fairly be ascribed to the improved drainage both of the towns and of the agricultural districts. The fact may be proved, did space permit; and the practical inference leads one to hope for still more immunity from diseases arising from this source, if the “proper authorities” direct further efforts in this direction. “Within the last half-century land-draining and town-sewering have ripened into sciences. From rude beginnings, insignificant in extent and often injurious in their effects in the first instance, they have become of the first importance. Land has, in many instances, doubled in value; and town-sewering, with other social regulations, have not unfrequently prolonged human life from five to fifty per cent., as compared with previous rates in the same district.” “Agues (and malarious cachexia?) are reduced. Since 1840 an annual mortality in English towns of 44 in 1,000 has been reduced to 27; an annual mortality of 30 has been reduced to 20, and even as low as 15; and human life has now more value in England than in any other country in the world—a result entirely due to better sanitary arrangements.” (Rawlinson, Journal of Society of Arts, March 21, 1862, vol. x, p. 276.)

The time indeed appears to have arrived when accurate sanitary statistics should not only be kept for all branches of the public service, but also by all corporations, municipalities, boards of commissioners, and parish vestries, for the population within their respective jurisdictions. Such statistics should be published at least once every year, as the natural history of the population. {Sanitary Statistics*, B., International Statistical Congress. London, 1860. Second Section.)

Animal Malaria Poisons or Effluvia.—Animal effluvia arise from the decomposition of the exhalations, excrements, or excretions of individuals (whether of mankind or of the brute creation), of filthy habits, or when crowded in confined spaces. Such poisons appear to be more limited in the causation of disease than the paludal poisons just noticed. We know little about them except that they are developed in situations where numbers are crowded together, as in prisons, hospitals, besieged towns, camps, ships, and such-like places. Winter is known to be favourable to their development and deleterious influences. They are sedative or depressing in their actions, and while they lower the energies of the nervous system, they tend also to corrupt or poison the blood, surcharging it with decomposing organic compounds.

Ephemeral febrile states are produced, and such conditions of ill-health are thereby established, so that a certain proclivity to the more serious and specific communicable diseases seems to be entailed. Conditions of the constitutions are brought about by which a certain receptivity or disposition of the blood is pro

CONDITIONS FAVOURABLE TO THE SPREAD OF DISEASE. 205

duced, rendering it more liable to undergo those changes which it undoubtedly undergoes during the progress of the specific diseases about to be noticed. Thus we have a predisposition to certain diseases brought about, and especially to such specific febrile affections as typhus fever, dysentery, cholera, and the like. Dr. Carpenter (than whom we have not a better physiological authority), in an interesting paper on the Predisposing Causes of Epidemics, shows that the conditions which tend to bring about the specific miasmatic diseases of the Zymotic class are referable to three categories:—

(1.) Conditions which may introduce into the system decomposing matter that has been generated in some external source.

(2.) Conditions which occasion an increased production of decomposing matter in the system itself.

(3.) Conditions which obstruct the elimination of the decomposing matter normally or excessively generated within the system, or abnormally introduced into it from without.

The decomposing matters generated in external sources may be enumerated as putrescent food, water contaminated by sewerage or other decomposing organic substances, and air charged with miasmatic emanations. The constant breathing of such putrescent effluvia may, by communicating a putrescent tendency to the blood, render it more prone to the changes by which specific poisons are multiplied. Ill-health and consequent receptivity for any specific disease poison are developed by the degeneration of the tissues within the body, such as occur in the puerperal state, after severe injuries, and as a consequence of excessive muscular exertion; and also by an insufficient supply of air, a high external temperature, and the ingestion of alcoholic drinks. Each and all of these causes tend to induce morbid conditions of the blood, a tendency to putrescence, and a condition of ill-health of the body.

Specific Disease Poisons.—The matter by which the specific miasmatic diseases are communicated and propagated is solely derived from the body of the similarly diseased human being; for there, during the course of the specific disease, is the soil in which the specific poison is bred to multiply and propagate its kind. It is not yet clearly established how far the bodies of animals may not be a soil for the propagation of diseases communicable to man. (See the Sections on Small-pox and Cow-pox.)

The diseases of the lower animals are not sufficiently studied by us. The diseases of plants are almost entirely neglected. Yet it is clear, that until all these have been studied, and some steps taken to generalize them, every conclusion in pathology, regarding the nature of the propagation and dissemination of specific miasmatic and even of parasitic, dietic, and enthetic diseases, must be the result of a limited experience from a limited field of observation. How do we know that the blights of plants, or the causes of them, are not communicable to animals and to man? We know how intimately related the diseases of man and animals are with famines and unwholesome food; and of famines with the diseases of vegetable and animal life, as much as with the destruction and loss of food.

Dr. Carter, of Bombay, has shown that there is in India a very singular, and although strictly endemic disease, yet a very prevalent one, which occurs in the hands and feet, especially the latter, and which it is probable is really of the nature of a “blight,” in so far as it is owing to the implantation in the tissues of “sporules or germs,” which in the progress of development commit irremediable ravages on the affected parts, leading ultimately to entire disorganization of the tissues. It is known as the “fungus disease of India,” and is described by Dr. Carter in the Transactions of the Medical and Physical Society of Bombay, No. 6, new series for 1860.

On the relations between the diseases of man and animals, and especially in connection with food, the reader is referred to a series of papers by the author, in the Medical Times and Gazette for 1857.

Dr. William Budd, of Bristol, has also recently directed attention to the occurrence of malignant pustule in England, in a paper read at the great meeting of the British Medical Association in London, in August, 1862. He has shown that the disease has not been so uncommon in England as had been supposed—that it is common and very fatal to oxen and sheep in this country—that in man and in sheep the disease is identical—that it is communicable to man by direct inoculation, and also by eating the flesh of the animals affected—that it may be conveyed and disseminated by the bites of insects, such as gnats—and that the disease may be recommunicated from man to animals. (Brit. Med. Journal, January 24, 1863.)

ENDEMIC, EPIDEMIC, AND PANDEMIC INFLUENCES. 207

There are some peculiar and characteristic features especially pertaining to the specific diseases of the Miasmatic order which require special notice as introductory to a description of the individual diseases :—

First, They may suddenly spring up in a localityunder unfavourable sanitary conditions.

Second, they may rapidly spread at irregular intervals, so as to incapacitate or destroy great numbers of people.

These two marked and striking features are technically described as being due respectively to Endemic and Epidemic influences, the nature of which will be considered in the following chapter.*

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CHAPTER III.

ON THE NATURE OF ENDEMIC, EPIDEMIC, AND PANDEMIC
INFLUENCES.

Endemic Influences result from those conditions or agencies peculiar to a locality which favour the development of various miasmatic diseases, and may thus account for their sudden origin. Such diseases are then said to be endemic. These endemic influences, for the most part, are exerted by the geological properties of a district, and are traceable to the constitution and state of the soil, water, and air; to elevation above the level of the sea, vicinity of sea, rivers, or stagnant water, woods, and vegetation; variations of temperature, prevalent winds; in connection with avocations, modes of life, quality of food and quantity, as modified by moral agencies, such as indolence or activity; privation and comforts, filth or cleanliness of people; together with their habits of life and employments, ignorance or mental culture; and, lastly, their social, moral, religious, and political conditions. It may be shortly stated in illustration, that endemic influences become mainly active through the following conditions, namely:—

* Deputy Inspector-General Dr. Lawson has recently called the attention of the profession to what he considers to be oscillations of influences over the whole world, determining febrile diseases. To such influences he gives the name of “Pandemic.” (Transactions of Epidemiological Society for 1862; also, Statistical, Sanitary, and Medical Reports of the Army Medical Department for 1801.)

1st. That the specific poisons by which the communicable diseases, such as small-pox or typhoid fever, propagate their kind are never totally in abeyance.

2nd. The specific communicable diseases are constantly extant somewhere, and only under conditions favourable to their dissemination do they spread or become epidemic. Although their germs, specific gases, active principles, or media of propagation and development may lie dormant or latent for a time, it is not to be inferred that they have ceased to exist.

3rd. The history of all the specific communicable diseases demonstrates the same alternations of slumber and activity; of wide-spread prevalence in one place, while neighbouring places may remain free; and finally, the same successive invasion of neighbouring places, such that the prevailing disease only begins to prevail in the new locality after it has already died out in the old.

4th. One element remains constant in the history of endemic influence, and that is the specific morbid poison which is the origin of each case. It is susceptible of transmission from place to place, and may gather strength as it proceeds, again to die out or become dormant, so that its track is with difficulty followed or traced out.

5th. In large cities such specific poisons are always more or less active, and their diseases always present; but in the country districts they only now and then occur. The occurrence of long intervals of rural exemption is not traceable to any feebleness of the poison to act; for, when the disease does become developed in these places, the ratio of persons or of animals attacked is incomparably greater than is ever seen in cities under like circumstances. (See Professor Acland’s account of the fever in Great Horwood in 1857-58; and Dr. William Budd, of Clifton, regarding fever at North Tawton; and his most instructive little book On the Propagation of Typhoid Fever.)

6th. In large towns the sewers are constantly charged with the materies morbi of specific diseases always abounding in towns. In small villages and other places, where no sewers exist, the air only may be infected, or the water contaminated, by the direct or indirect importation of cases of specific disease or their equivalents—the poison itself—so that the organic impurities, the dung-heaps, the open soil which surrounds the dwellings of the patients, the cesspools, and the privies common to several houses, gradually but eventually become impregnated with the specific poison of the disease. Thus the atmosphere of the village may become incomparably more virulent than the atmosphere of the sick-chamber

PROPAGATION OP DISEASE BY CONTINUOUS SUCCESSION. 209

itself. Hence the rapid epidemic spread of the miasmatic diseases in the limited space of rural villages; and which gives rise to the popular error, that such diseases are invariably contagious in country places, and only rarely so, or by exception, in cities or large towns.

7th. All these specific diseases multiply their kind after similar modes of propagation.

8th. All of them establish a constant series of morbid changes and lesions, and always issue in the reproduction of its own specific germ, miasm, gas, morbid poison, or active principle by which it propagates its kind. Thus small-pox propagates small-pox; measles multiplies measles; scarlatina reproduces scarlatina; typhoid fever breeds typhoid fever; typhus, typhus; and so on. In the terse language of Dr. William Budd,—

“What small-pox and measles were in the Arab in the days of Rhazes, they still are in the London Cockney of our own time. What they are in the London Cockney, they are in the wild Indian of the North American prairie, and in the Negro of the Gold Coast. To all the other specific communicable diseases, as far as our records go, the same remark applies. In races the most diverse, under climates the most various, age after age, through endless generations of man, these diseases pass down through the human body (sometimes through animals—e. g., bovine small-pox?), perpetuating their own kind, and each maintaining its separate identity, by marks as specific as those which distinguish the asp from the adder, or the hemlock from the poppy.”

Such being the case, it is difficult to conceive (as Drs. Watson and William Budd most justly observe), “that diseases of whose propagation this is the history can ever be generated in any other way.” Most of these miasmatic diseases also are peculiar to man; while animals on their part are infested by a whole brood of communicable diseases—no less specific in their kind, each distinct from the other, and most of them, although some may be communicable to man, are incapable of multiplying in the human body. Cattle appear to be subject to a variety of malignant and communicable fevers, from which man is altogether exempt.

9th. Certain receptive conditions, or a predisposition (the nature of which is unknown), exists in individuals which appears essential to the development of the specific poisons and the establishment of the disease; and immunity against a repetition of the disease is generally conferred by one attack of the same disease—an immunity which has been proved by experiment on an enormous scale with regard to small-pox; and with regard to the other diseases of this kind, the belief in such immunity is deduced from extensive observation. But the immunity acquired by one attack of any of these diseases is of no avail against the rest. Measles, for example, renders the body proof against measles, but leaves it as open to small-pox as before, and so on of the rest.

10th. With regard to fermentation, putrescency or decomposition, there is some reason to believe (as shown in the previous chapter) that it may quicken the activity or facilitate the development of specific morbid poison, in the way of a predisposing cause. Dr. Budd, however, believes that this effect has been much overrated, notwithstanding the observations of Dr. Carpenter referred to in the preceding pages. Nevertheless, there is no small amount of circumstantial evidence tending to show that endemic conditions may be thus far favourable to the propagation of specific diseases, even to the extent of epidemics, in consequence of the predisposing agency of putrescent emanations; and, on the other hand, both endemic and epidemic influences are often held in abeyance by the tendency to decay, decomposition, and destruction of the specific germs, miasms, gases, or disease poisons themselves. They are stamped with the tendency to change and to perish. Like all organic substances which propagate- from minute or invisible beginnings, myriads perish for one that is fruitful. This is especially demonstrable in respect of the Parasitic diseases, whose germs would overrun the world if they all came to maturity; but the extinction or the dispersion of the specific poisons is abundantly provided for through the operation of many natural causes; and by imitating some of these operations of Nature we may be able eventually to exterminate, or, at all events, greatly to modify the severity and reduce the mortality from many of these diseases.

The belief in the spontaneous endemic origin of the specific miasmatic diseases rests on evidence entirely negative—namely, the fact that cases do spring up in which it is impossible to trace the disease back to a personal source of specific propagation and dissemination—an event which is inherent in the very nature of these diseases. For the active principle of the poison is invisible, although the matter that is known to contain it may be capable of isolation and inoculation, as in small-pox; yet the existence of

QUESTION OF THE SPONTANEOUS ORIGIN OF DISEASES. 211

the specific disease poison, is known to us by inference only. Again, we know that ample provision is made and ways are open for the dissemination of the active agent of propagation in a thousand unseen modes, so that it is obvious that the precise source of infection and its track must often baffle the wisdom of man to discover or trace out.

Cases thus constantly arise which appear to give countenance to the belief that the disease has had a spontaneous origin— sporadic, as it is termed. Numerous cases of small-pox occur which can never be traced to their source, or to communication with persons similarly diseased; yet the history of small-pox is decisive against the notion of its spontaneous origin; and if of small-pox, so for all the other specific Zymotic diseases of the same nature. Dr. Watson has well observed that “the small-pox never occurs except from contagion. It was quite unknown in Europe till the beginning of the eighth century. No mention of any such malady is to be found in the Greek or Roman authors of antiquity. Now, whatever may have been the deficiencies of the ancient physicians, they were excellent observers and capital describers of disease; and it is impossible that a disease so diffusive and marked by characters so definite and conspicuous should have escaped their notice, or have been obscurely portrayed (if known) in their writings. On the other hand, Mr. Moore, in his learned and interesting History of Small-pox, has shown that it prevailed in China and Hindostan from a very early period—even more than a thousand years before the time of our Saviour. That it did not sooner extend westward into Persia, and thence into Greece, may be attributed partly to the horror which the disease everywhere inspired, and the attempts that were subsequently made to check its progress, by prohibiting all communication with the sick, partly to the limited intercourse which then took place among the eastern nations, but principally to the peculiar situation of the regions through which the infection was diffused, separated as they are from the rest of the world by immense deserts and by the ocean.” (Watson, Lectures on the Practice of Physic, 3rd edition, vol. ii., p. 709.) “If anything were wanting,” writes Dr. Budd, “to show what is the true inference to be drawn from these events, it would be found in the fact that, once imported into the West, it spread with the most fearful rapidity and havoc; and that while almost all men are prone to take the disorder, large portions of the world have remained for centuries exempt from it, until at length it was imported, and that then it infallibly diffused and established itself in those parts. In this country the (endemic) conditions for the spread of the disease existed in the most intense degree, as was shown by the event when the disease was once introduced. The long lapse of ages during which we remained entirely free from small-pox showed, with equal clearness, that, until this introduction occurred, all the conditions favourable to the development of small-pox were powerless to cause a single case. The spectacle witnessed in Europe was repeated over again in the Western World in a still more striking way. Our knowledge of the events here is precise and sure. There was no small-pox in the New World before its discovery by Columbus, in 1492.  In [l”)17tlie] disease was imported into St. Domingo. Three years later, in one of the Spanish expeditions from Cuba to Mexico, a Negro, covered with the pustules of small-pox, was landed on the Mexican coast.  From him the disease spread with such desolation, that within a very short time, according to Robertson, three millions and a half of people were destroyed by it in that kingdom alone.” Again, “Small-pox was introduced into Ireland in 1707, when sixteen thousand persons were carried off by its ravages—more than a fourth part of the whole population of the island. It reached Greenland still later, appearing there for the first time in 1733, and spreading so fatally as almost to depopulate the island.” (Budd, 1. c, p. 35, et seq.) No common conditions of human life gave rise to such phenomena. Propagation from the actual poison of a pre-existing case was the one necessary and all-sufficient condition for these endemic outbreaks and their epidemic prevalence. The precise mode in which the miasmatic diseases, with their specific poisons, first came into existence is beyond our ken—hidden from us as yet by a veil, and remaining an inscrutable, at least an unpenetrated, mystery. But, everything tends to show that, once created, they all propagate only in one way, namely—by continuous succession.

Defective ventilation, inasmuch as it is always injurious to health, always tends to cachexias—always, also, aggravates disease, and so promotes the endemic influence. With regard to any influence it may have on the development and spread of communicable disease, it may be noticed that it does not equally help

NATURE OF EPIDEMIC INFLUENCE. 213

all communicable diseases to develop themselves and to spread. Commonly it seems to operate in proportion as the specific miasmatic disease is one which imparts specific poison properties to the general exhalations of the sick. The significance of defective ventilation is not likely, therefore, to be quite the same where typhoid fever, cholera, or dysentery are the prevailing diseases, as where the disease is typhus fever, scarlatina, small-pox, or diphtheria. In the cases of typhoid fever, cholera, and dysentery, any defect of ventilation would become more and more important in proportion as the bowel discharges of the sick were not promptly removed from within doors, or as, from other causes, there were fecal effluvia or excrements suffered to remain in the dwelling. (Simon, Third Report of the Medical Officer of the Privy Council, 1860, p. 10.)

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Epidemic Influence.—The second characteristic feature peculiar to some of the miasmatic order of Zymotic diseases, is, that they sometimes spread rapidly, so as to incapacitate and destroy great numbers of the people. The disease is then said to be epidemic (epi, upon; and demoe, the people). No subject has afforded greater scope for speculation than the origin, cause, and progress of epidemics. It is in vain to speculate upon the subject; and, in the words of Dr. Wood, of Pennsylvania, “all we can say, with certainty, regarding epidemics, is, that there must be some distempered condition of the circumstances around us—some secret power that is operating injuriously upon our system—and to this we give the name of epidemic influence or constitution,” and which is believed to predispose towards the receptivity of specific disease poisons. The observations, also, of Mr. Simon lead to the belief that the prevalence of external conditions, tending in certain localities to determine a specific decomposition of excrement, communicable to other organic substances and infecting the air, is an essential element in an epidemic period.

The most recent speculation regards the discovery of a peculiar atmospheric condition, ascribed to a principle called ozone, or osmazone (osmi, stink, or azone, smell), of which, as yet, we know nothing definite; although many subtle instruments and apparatus are in use to detect and measure the amount of this principle in the air.

A careful study of the effects of the epidemic influence appears to warrant the enunciation of certain laws which seem to regulate its operations. These laws are thus condensed from the statements of Dr. Wood:—

Laws of Epidemic Influence.

(1.) This influence frequently predisposes to diseases, apparently independently of any other known cause, as in the case of influenza and cholera. It makes itself manifest, also, by appearing to give increased energy to causes which produce particular diseases: so that small-pox, scarlatina, typhus, and the like, sometimes rage with great violence as epidemics. It also appears to predispose to new and anomalous forms of disease, as witnessed in the furunculoid epidemic, which recently prevailed both in Europe and America, from 1849 till 1852.

(2.) Sometimes the epidemic influence manifests itself by a certain type or direction, which existing diseases appear to take. Thus at one period diseases take a low, or what is called a typhutid typo, so that depletion is not tolerated; at another time, an inflammatory tendency predominates, and antiphlogistic treatment is required. At one period, also, there is a tendency in disease to complicate its course by a disposition to affect particular organs. At one time head affections predominate; at another time affections of the chest, or of the alimentary canal, com plicate the course of a prevailing disease. Consequently the same disease may demand very different, and even opposite modes of management.

(3.) During epidemics other diseases are apt to osmium more or less of the prevailing epidemic features. Thus, when cholera prevails, looseness of the bowels often complicates the course of other affections. When influenza prevails, catarrhal complications increase the danger of other diseases. Ill-health of any kind, therefore, favours the action of the epidemic influence.

(4.) Some change in the character of prevailing diseases of a constant and recurring kind often indicates the approach of an epidemic and the prevalence of the epidemic influence.

(5.) The first effects of the epidemic influence are usually the most violent and marked, and the cases of the epidemic disease become mild as the epidemic influence passes away.

(6.) The epidemic influence sometimes disappears entirely after a short prevalence; sometimes continues with irregular intermissions for two, three, four, or even six years, or longer. Influenza and cholera are examples.

(7.) An epidemic tendency, after continuing for several years, may give place to one of a different kind, which, in its turn, may again give place to the first. Malarious fevers, yellow fever, and

PANDEMIC OSCILLATIONS OF DISEASE. 215

typhus illustrate this in America. The eruptive affections seem to run in somewhat similar cycles. After the introduction of vaccination the small-pox seemed for many years to be almost entirely subdued; but more recently again the disease has seldom been entirely absent from among us, alternating as an epidemic now and then with measles, scarlet fever, and typhus. We look forward to the time when vaccination, enforced by law, will predominate, and in time completely eradicate the disease.

(8.) The lower animals are also subject to epidemic influences; and seasons of unusual fatality among them have coincided with those in which the human race have suffered. This fact has been well shown in an elaborate and erudite analysis of the census of Ireland, by Mr. William R. Wilde, of Dublin, the diseases of the population having been recorded at the time.

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Pandemic Influences,—The expressions of the hitherto prevailing doctrines regarding endemic and epidemic influences appear so unsatisfactory to many minds, and leave many circumstances regarding the spread of diseases unexplained, that attention is being directed to more comprehensive views and investigations of the questions involved in the preceding paragraphs. An ingenious theory has been propounded by Deputy Inspector-General Dr. Lawson, as already mentioned in a note to page 207. Dr. Lawson has attempted to establish the occurrence, between 1817 and 1836, of a series of oscillations of febrile diseases, following each other over the world with amazing regularity. The mode of occurrence of such febrile diseases he attributes to a cause or influence which, from its extent and progressive character, he names a “pandemic wave,” to distinguish the influence from that usually understood as epidemic, referring to a single form of disease affecting a limited space. Under the influence of this pandemic wave Dr. Lawson believes that there is a constantly progressive tendency to the development of all and various endemic febrile diseases in the Atlantic and Western parts of the Indian Ocean, from South or South-east to North or North-east.

But the facts and data on which this theory is made to rest are not of sufficient number, and many of them are not sufficiently trustworthy to rest a judgment upon. In not a few instances, also, a totally different interpretation may be given to that which Dr. Lawson has assigned to them. Although, therefore, it may be premature to propound such a theory, especially as it is still open to the verdict of “not proven,” yet the expression of it is calculated to do good by drawing attention to the subject, and to the comprehensive, world-wide range which must be given to such investigations; and to whom can Science look with more hope for results than to the medical officers of Her Majesty’s British and Indian armies?

A successful study of these peculiar and characteristic features of miasmatic diseases, namely, the endemic, epidemic, and pandemic influences, is of the utmost importance to the student. He will learn to appreciate how much and successfully mortality may be diminished by well-directed hygienic measures: such as, cultivation and improvement of the soil, extension of commerce, improvements in diet, and the social circumstances of the lower classes—especially in regard to cleanliness, ventilation, and domestic management of improved dwellings, and efficient sewerage; care in the separation and treatment of the sick when in numbers, and the use of strict measures of a prophylactic kind suited to the circumstances of the case. Next to large towns, the health of the Army is of the greatest importance, especially when we consider the tendency that exists to a high rate of mortality in that service. In the military age (which is the age between eighteen to forty) the mortality of the general population in England is less than one per cent, per annum. The mortality of the British army is much above this. On Home service it has had a mortality double that of the civil population at the corresponding ages; and seven-ninths of the entire mortality among the infantry of the line has arisen from diseases of the Zymotic class. Disease and mortality are much greater during campaigns, when more than twenty-two per cent, are constantly on the sick list. The causes of high rates of mortality require constant investigation, by carefully observing, recording, and comparing the facts over a sufficiently large area, thus arriving at certainty as to the causes, and whether they can be mitigated or removed.

An observation of great interest in connection with animal malaria poison, as well as with epidemic influences, may be appropriately referred to here. It seems clearly proven, especially by the valuable and decisive observations of Dr. William Budd, of Bristol, that the communicable poison property of typhoid fever and of cholera are capable of being imported or carried

PROPAGATION OF TYPHOID FEVER AND CHOLERA. 217

from place to place by persons who have the disease. Dr. Budd’s history of the North Tawton fever and its offshoots (Lancet, July 9, 1860) is most conclusive on this point. His arguments are also cogent to the general effect, that specially the bowel discharges are means by which a patient, whether migrating or stationary, can be instrumental in disseminating typhoid fever and cholera. Mr. Simon makes the important remark, however, that these bowel discharges may not be the sole means of multiplying and disseminating these diseases; although, provisionally, the conclusions of Dr. Budd must be acted upon in their present unqualified form; while it is of the greatest practical importance to learn, as exactly as possible, whether it is in all states of the disease, and under all circumstances, that the bowel discharges of typhoid fever and cholera can communicate and multiply the means of dissemination. In illustration of such possible contingent results, Mr Simon refers to some interesting and important experiments made in 1854 by Professor Theirsch, of Erlangen. These experiments seemed to show that cholera evacuations, in the course of their decomposition, either acquire the power of communicating or multiplying their specific poison, or that the specific poison inherent in them becomes intensified by decomposition (Zymosis?) That the decomposition or change may begin even in the bowels, after the secretion and accumulation of the material in them, as well as in cess-pools, seems to be possible; and perhaps, as Mr. Simon justly remarks, may furnish an explanation of the many cases in which human intercourse has apparently disseminated the disease. For, according to the observations of Professor Pettenkofer at Munich, and Professor Acland at Oxford, it would seem that during cholera periods the immigration of persons suffering diarrhoea has been followed by outbreaks of cholera in places previously uninfected; and Professor Pettenkofer ascribes this fact to an influence (Zymotic?) exerted by the faeces of such diseased persons in the cess-pools and adjoining soil of ill-conditioned places to which they go. Specific poison properties of this kind would thus probably extend to the polluted well waters of such soils, and might thus render them, if swallowed, capable of exciting cholera, or typhoid fever, or dysentery, by direct contagion. It is encouraging to sanitary reformers, as Mr. Simon justly remarks, that cases of the apparent introduction of cholera contagion by human intercourse are essentially different from cases of the dissemination of such specific diseases as small-pox or measles. The multiplication of the specific poison in the latter diseases takes place exclusively within the human body. The multiplication and dissemination of them have no immediate dependence on differences of medium; but wherever human beings can cross one another’s path, to the susceptible-or unprotected person these specific diseases may be communicated. On the other hand, it seems really to be the fact that the cholera poison (and probably, also, typhoid fever poison and dysentery), if it can at all be multiplied within the body, almost certainly has its great centres of multiplication elsewhere; namely, in those avoidable foci of corruption where excrement accumulates and decays. Military authorities ought to remember this fact. They have had abundant evidence of it in the old camping grounds of the Indian army; as well as when following the route and encamping on the ground previously occupied by retreating armies. For disseminating the disease and multiplying the poison, foulness of medium seems indispensable; and it is no ordinary foulness which will impart to air, food, or water the Zymotic action of decomposing excrement. The common taint is something specific. Therefore, as regards cholera, it seems highly probable that the immigration of infected persons might occur to a very great extent without exciting epidemic outbreaks, if such immigration were only made into places of irreproachable sanitary conditions, especially as regards water supply, and the continuous removal of house refuse or camp filth. (Compare Simon in his public health reports— especially second and third—relative to the people of England; also Pettenkofer, Aclaud, and Thiersch, as quoted by Simon, p. 3 of his third report, 1860.)

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