See also:

“Professor Mitchill (sic) has always entertained an opinion favourable to the existence of an element in nature which might be called phlogiston.”

Biography and Background

Dr. Samuel Mitchell (1764-1831) was the Chief Editor of the Medical Repository during its first years of publication in the early 1800s.  This was the first medical journal to be published in association with the New York School of Medicine following the nation’s recovery from the Revolutionary War.    There was only one other school active at this time with its own medical journal, the School of Medicine in Philadelphia, Pennsylvania, the place of work for the famous Benjamin Rush.

New York and Philadelphia were informally competing with each other at this time for top position in the academic world with regard to the knowledge, practice and academic teaching of medicine.  Like any two professors engaged in such an intellectual competition, each had their own philosophy, and to members the local communities and medical societies in New York, Samuel Mitchell’s teachings won out for the most part over those of Benjamin Rush.  One of the most impressive aspects of Mitchell’s teachings was his multidisciplinary nature.  Unlike Rush, whose forte was in medicine and pathology, Mitchell’s forte was in nearly all of basic and natural science fields.  In terms of day-to-day knowledge and the impact of this knowledge on people in general, Mitchell’s coup de grace was his ability to outshine anyone devoted to the sciences, perhaps even Benjamin Franklin.  This was not a claim that Benjamin Rush would dare state openly about himself. (Although communications with his wife suggest Rush was overly narcissistic about his accomplishments and fame; perhaps too certain of himself and almost god-like at times, a behavior still common to certain parts of this profession.)

The single most important aspect of Mitchell’s philosophy was his belief in the Phlogiston theory for disease.  Phlogiston, when it was first invented, was this invisible substance matter (and people) emanated, a kind of invisible substance capable of passing the contagion or other cause for illness from one place to the next, one body to the next, one state of existence to the next.  For Mitchell, this phlogiston had something to do with oxygen and was somehow related to all of the newly discovered forces and force-related events of nature, ranging from the formation of meteors and simple rain, to the results of a volcanic explosion and the rumblings of an earthquake.  Therefore, according to Mitchell’s philosophy, in order to understand the natural causes for disease, we had to understand the causes and reasons for each and every natural event to take place in the local natural history.  This reasoning enabled Mitchell to begin to take on a number of topics never previously linked to medicine, and once Mitchell’s long-lived influences subsided, never really made their way back into the medical books for the most part.

In the long run, Rush was younger than Mitchell and perhaps in some ways induced changes that outlived Mitchell’s influences.  As medicine changed from being a natural science based profession to the form that it is today, a profession devoted to physiology, pathology, psychology and philosophy (the four ‘P’s of old-time antebellum medicine), we see even more of Rush’s influence still bearing some importance in understanding some of the current medical teachings.  Mitchell’s teachings in the meanwhile, focused in some unusual ways of natural science and medicine, have important influences on the way that medicine still evolves.  In recent years, and medicine has once again tried to take a closer look at geography and disease and nature and disease, some of Mitchell’s writings once again become important when trying to understand these new interdisciplinary traits of the field of medicine.  The following article by Mitchell is an example of the logic and philosophy that existed during the years when medicine and disease, were highly dependent on what we knew about nature and how we interpreted these observations as important clues to medicine and disease.

We are provided important insights into the philosophy that Mitchell and many of his New York colleagues held, by the nature of the writings that Mitchell helped to directly promote being published in the Medical Repository.   The following are two examples of these writings.  These writings tie together the reasons why physicians could philosophically related natural elements, forces and energy, to the cause and nature of the diseases of the body.   This belief in the natural causes for diseases would persist for decades and generations to come, well past the Civil War Era.  They would only ultimately succumb to just one finding and its very slow acceptance by the medical community–the bacterial theory for disease considered to be finally completely proven and understood during the early 1880s, nearly 15 years following its first published proofs.

The first article is Mitchell’s synopsis of his belief, presented just before he took a state senator position.  The second article is an example of how he applied this philosophy to the acts of nature, indicated by by recommendation of an article by one of his colleagues who believed the same for publication.

For more on Mitchell see:


To put this more into perspective, see my writings on Noah Webster’s theory of climate and disease, and his use of this philosophy to explain the causes for the major epidemics of the Hudson Valley, for the years 1793-1815 approximately.  See also the writings on the Livingstons and Bartow White.

Numerous examples of Mitchell’s writings on the theory for disease were published during the earliest years of the 19th century.  A number of these in my possession are in the plans for later presentation.

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Outline of Professor Mitchill’s Lectures On Natural History, in the College at New-York, delivered in 1809–10, previous to his departure for Albany, to take his seat in the Legislature of the State.

THE subjects of this extensive course are divided into distinct heads, after the following arrangement: He begins with the history of the earth, as a planet or integrant portion of the universe. 1. It is divided into four parts : 1. Cosmogony, embracing the doctrines relative to the origin. ‘ of the world. 2. Geognosy, or the account of the changes it has undergone in the chaotic state, during the deluge, and since that event. Its constituent parts viewed under five divisions ; (a) Primaeval, or such as were formed at the creation, or deposited from chaos immediately after, such as syenite, topaz-rock, quartz-rock, primitive flint, slate granite, gneiss, micaceous slate, argillaceous slate, serpentine, with primitive lime-stone, gypsum, and trapp. . (b) Transition, or such as were formed when a further subsidence from the original medley of things, took place, of which, transition lime-stone and trapp, grey wacke, flinty slate, and transition gypsum, are examples : (c) Flat or Secondary, to wit, sand-stone, low stratified lime-stone, gypsum and trapp, rocksalt, chalk, and coal: (d) Alluvial, formed more recently still by settlement from water, constituting the bottoms of valleys and level spaces between mountains, as well as the chief constituents of widely extended plains, (e) Volcanic, or the products of subterraneous fire, comprehending lava, slag, ashes, scoriae, &c. In this arrangement he follows the system of the distinguished German, professor Werner. He is a firm Neptunian, and examines at great length the operation of water in giving configuration of the globe. 3. Mineralogical Chemistry, or an explanation of the properties of matter, attractive and repulsive, by which its different forms and modifications are effected. 4. Physical Geography, or an account of the actual condition of the globe, as to land and water, mountain and valley, continent and island, mine and surface. This section of the course is denominated Geology.

2. The history of Light, as the most copious of created existences, and occupying the widest space in the universe. It is considered as a body rendered fluid by means of heat or caloric, like other bodies, and like them, giving out; its heat on its decomposition. A review is given of the modern discoveries ‘by Bancroft, Herschell, Ritter and Wollaston, rendering it necessary to enlarge and reform the doctrines of Newton, and inclining him to the belief that the sun-beam consists of two ingredients, colour and caloric. Hence is deduced a theory of Colour and Heat as evolved from light by its decomposition, and imparting to every thing its proper hue and temperature. White is considered a chemical, and black a mechanical assemblage of all colours ; and Rumford’s considerations on the black clothing, furs and skins of animals, and on the black coating of other bodies in relation to heat, are exhibited to strengthen this argument. The analogy between light and sound is traced, to shew the doctrine embraced by some, that impulse or vibration may be of great efficacy in bringing about the phenomena of light. This part of the course is termed Photology.

3. Heat is next considered, and its natural history attempted. A great source of it is the sun-beam, or chemical compound of colour and light. Another copious source of it is the oxygenous fluid of the atmosphere, or phosoxygenous gas as it ought to be called. If the sun-beam becomes associated with oxygen, it forms the compound erroneously called oxygenous air. It is really a solution of oxygen in fluid light, and on the resolution of this compound into its constituent parts, heat, light, oxygen and colour come forth. After considering the mechanical and chemical theories of fire, a preference is given to Pictet’s arrangement of the facts under four heads, to wit, the free, latent, specific and fixed forms of heat. Its effects are considered as producing contraction, expansion, liquidity, fluidity, fusion, and as the great stimulus to vegetable and animal life. The plutonic hypothesis is examined and rejected. This branch of the course is called Pyrology.

4. The history of water is the next subject of Professor M.’s discussion. It is the great agent in effecting the changes the earth has undergone. The proofs are stated of its having covered the mountains, and of its separation from the materials with which it was anciently blended, forming thereby the stratification illustrated under the head of Geology. Reasons for supposing the waters of the globe to have undergone a diminution ; 1. in the formation of crystalline bodies ; 2. in the constitution of the atmosphere; 3. in the formation of plants ; and 4. in the organization of animals. By these processes an immensity of the water which existed at the flood is converted into solid forms, and a correspondent shrinking of the ocean has ensued. In these natural and easy ways, is the problem solved, which the ingenious Jamieson gives up in despair, that is, what has become of the surplus water that once deluged the world ? The primitive inundation having thus subsided, the question is examined, whether the quantity of water is yet diminishing, as some of the modern philosophers think considerations are offered in favour of such a belief, in consequence whereof preparation is making for the final consummation of terrestrial affairs by fire. Waters apparently rushed from the south, according to Kirwan’s doctrine. Questionable whether water can be decomposed as the fashionable chemists think, and whether it is not an element as the ancients and Priestley contended. It is divisible into three historical sections. 1. Salt water, such as saline or briny fountains, the ocean, the Mediterranean, Euxine, Caspian, and Judean seas; and the Nitrian and Mexican lakes. 2. Fresh water, such as the fluid of rain, dew, snow, and hail; spring or fountain water; river water, and the liquid of the great American lakes, as well as of many more inland collections of water. 3. Mineral water, such as the acidulous springs of Ballstown, charged with carbonic acid; the sulphureous springs of Clifton in Ontario county, exhaling hepatic gas, and depositing brimstone ; the thermous springs of Lebanon, which are of a temperature fitting them for an exquisite bath ; the chalybeate springs of many places in our granite country.  These inquiries, with a multitude of explanations concerning tides, currents, alluvions, and solutions, are distinguished by the title of Hydrology. 5 . The globe having been thus viewed as to its geological structure, the effects wrought upon it by light, heat, and colours, and lastly in respect to the alterations it has sustained by means of water, the next view taken of it relates to its atmosphere. The idea of Lavoisier is here adopted, that every thing which the heat of its surface can convert to air or gas, makes a portion of the sphere of vapours encircling our planet.. In order however to comprehend the real constitution of the atmosphere, a wider range is taken; for its materials as we find them are divisible into two classes, the mechanical and the chemical. To the mechanical ingredients of the atmosphere belong dust, sand, leaves, soot, carbone, ashes, and whatever wind and fire can elevate ; such as metallic particles, earths and alkalies, and seasalt in maritime situations. Diffusion of odours, and the particles emitted from the materials in tradesmen’s and manufacturers’ shops, all add mechanically to the volume of the atmosphere, as do exhalations from an infinity of other subjects. The chemical materials of the atmosphere are principally four gases : 1. Azotic gas. This is probably the oldest portion of the atmosphere. It is the easiest to volatilize, and the most difficult to condense ; and therefore in all likelihood rose soonest out of chaos. From its azotic and aphlogistic character, it is exactly adapted to the reign of night and death, when darkness hovered over the face of the deep. There is reason to suppose it a metal existing ordinarily in a gaseous state, as quick-silver in common temperatures melts into a fluid ; and its metallic constitution renders it a good conductor for electricity. By the last experiments, it is found to constitute almost four fifths of the atmosphere, or at least 783 parts of a thousand. 2. Oxygenous gas: This would seem to have made its appearance next, being first evolved from water by acute and cuspidated bodies of all kinds. These exist on the plants which may be supposed to commence their growth in the ocean,or under water,and to have added to the sum of oxygenous gas. Afterwards terrestrial vegetables sprouted up on the dry land, and added further to its quantity. Thus the atmosphere appears to have been gradually and duly prepared for the creation and nutrition of animals. Oxygenous gas makes up the chief residuary portion of the atmosphere; or as the latest analyzers say, 210 parts of a thousand. 3. Carbonic acid gas : This is affirmed to amount to about four parts in 1000; and consequently does not impart much distinctness of its character to the atmosphere. It however exists in various places, as in certain wells, mines, vats, vaults, caverns, and places where it is compounded or evolved in different processes.

The relative weights of these three gases are, that oxygen gas is rather heavier than azotic, and carbonic acid gas possesses greater weight than either separately, or than both in their atmospheric mixture. 4. But there is a fourth gas called inflammable air, which by reason of its numerous affinities and its trifling specific gravity, is capacitated to act a remarkable part in the atmosphere. Experimenters declare that it naturally exists in the atmosphere to the small amount of 3 parts in 1000. Its specific gravity is so moderate that a cubic foot weighs only 41 grs. twenty-six hundredths, while the same quantity of oxygenous weighs 1 oz. 1 dr. 51 grs. of azotic 1 oz. 0 dr. 39 grs. five hundredths, and of carbonic acid gas 1 oz. 4 dr. 41 gr.

5.  Professor Mitchill has always entertained an opinion favourable to the existence of an element in nature which might be called phlogiston. He pronounced a warm eulogy upon the genius and merits of professor Stahl; and he commended the resolute spirit of Priestley, who expired bearing testimony against Lavoisier and the Neologists of France, and their proselytes. M. had expressed his sentiments against the part of their nomenclature which insisted on the unity and simplicity of sulphur, phosphorus, and the metals as long ago as 1798 : and he proposed in a chart of chemical nomenclature, which he published in 1802, to strike out hydrogen altogether, and substitute phlogiston in its place. This amendment he actually made, and has adhered to it ever since. The fault of the phlogistians heretofore had been that while they were generally right, they were particularly wrong. By not defining specifically what their phlogiston was, their adversaries got the advantage of them, and when these expunged the very name and inserted hydrogen in its place, the phlogistians were almost totally prostrated or converted. But the creation of an hypothesis and the publication of a technical arrangement of terms to support it, could not alter the nature of things. Phlogiston continued to associate with sulphur, phosphorus and coal, as it used to do before the nomenclature was fabricated, and the metals, from platina down to chrome, attracted it as strongly as ever. He considers the table of Parisian chemical nomenclature as having been made prematurely, and as now presenting a stumbling-block to science. In their zeal to cry down phlogiston, its authors have done great injury to the cause of truth.

Now Dr. M. says, that the basis of inflammable air, is Phlogiston ; the material, as its etymology imports, that burns with flame or blaze. He observes, that this element has many and powerful connections ; among which those it forms with sulphur, phosphorus, coal, and the whole class of metallic substances, are some of the most distinguished. Consequently, every one of these natural bodies. instead of being simple or unmixed, is a compound formed of phlogiston, united to a sulphuric, phosphoric, carbonic or metallic base. This proneness of phlogiston, to combine with other natural bodies, renders it wonderfully instrumental in the economy of this world ; not only by its presence and agency in the composition of terrestrial beings, but by the functions it performs in the atmosphere. Dr. M. had visited the fountain of inflammable air near Niagara; he had often extricated it from iron and zinc; he had witnessed its burning vapour on the surface of brimstone, coal, and oil ; and had satisfied himself, by experiment and observation, that this phlogistic gas was both capable of uniting with sulphuric, phosphoric, and metallic bodies, in their solid forms, and of dissolving them and carrying them aloft in the air in its fluid form. The chief difference in the two cases was, that in the former the metallic and other bodies were relatively heavy, and the phlogiston light ; while in the latter, the inflammable air was abundant, and the metal, or other substance small. In the one, the metal, or other matter, was weighty enough to bind the inflammable principle to solidity, and to earth ; in the other, the inflammable air having broken its chains, ascended in company with a relatively small proportion of metallic or other matter into the upper regions of the atmosphere. And for the performance of this service, Prof. M. thinks it singularly adapted, since the body possessing the smallest specific gravity, is, by virtue of its strong attractive power, enabled to raise to remarkable heights, particles of those bodies which.possess the greatest.

He thus considers this offspring of phlogiston, inflammable air, as elevating to different altitudes in the atmosphere, sulphurous and metallic particles; which are precipitated per se, or formed into new combinations, whenever the inflammable air in which they are dissolved, and by which they are suspended, shall discharge them, or let them go. The phenomena of meteors, and fiery lights in the atmosphere, receive a happy solution from the application of these principles.

But M. does not stop here. He brings into notice the important, though neglected experiments of Margraff, Boyle, and Boerhaave, proving that rain-water always contains a portion of earthy matter in solution. These interesting facts it has been convenient to overlook, because they could not be reconciled to the fashionable hypothesis. The sound interpretation however of those facts, is, that earths are not only soluble in water, but also mount with it as high as it ascends, and are precipitated either with it when it falls, or without it when they enter into other combinations.

On these considerations, he explains the formation of meteoric stones in the atmosphere, without fetching them from the moon. Rejecting that extravagant notion, he derives the materials of the aerolithes, partly from the inflammable air, and partly from the watery vapour, which held them in solution. On their precipitation, the particles associate from aggregative and chemical attractions. The materials are all such as this earth affords. There is no new element among them, as might be expected if they came from another planet. It is in their arrangement of combination only that they form a sort of mineral, unlike any hitherto discovered on earth. And this we should, a priori expect, from the reflection, that they are formed in a peculiar manner, whereby a mixture sui generis would naturally, and indeed necessarily, be produced. And this explanation applies as well to those scorified stones that, as Branson and Silliman finely describe, fell from the atmosphere in Connecticut, during December, 1807, with the marks of recent fire every when’ visible upon them; as to those other aeranthes, mere aqueous aggregates that descended in France, during July, 1808, as Mr. Saint Ursin relates, all incrusted with hail.

These views of the atmosphere, with a theory of the winds, and an abundance of other particulars, are summed up under the name of Aerology.

6. Mineralogy is the sixth division of the subject, and comprehends the classification and particular description of those substances that were mentioned in a general and comprehensive way, under the head of Geology. On account of the very recent discoveries, which have enriched and ennobled science, Prof. Mitchill has found himself obliged to discard the quadruple arrangement of minerals, by Bergman, into earths, metals, salts, and inflammables. Although this distribution had received the respectable sanction of Cronstedt, Magellan, Kirwan, and the chief of the modern worthies who have cultivated an acquaintance with fossils ; yet its incompatibility with the present state of facts and observation, render it absolutely improper to adhere to it any longer. That fourfold classification was the most scientific and luminous that had been thought of; and was well worthy of the fond reception it met with. But it is now time to • change it for a better; for one which is framed and erected on the actual relations of minerals, as now understood. The arrangement he proposes is grounded on his own views of this department of knowledge, and on the penetrating discoveries of Prof. Davy. The prominent featnres of these joint and concurring testimonies are, the relations which mineral, and especially metallic bodies have to Phlogiston, and to Oxygen : to which may be added their relations to Sulphur, to Each Other, and to Acids.

I. The first class comprehends minerals, as combined with phlogiston, (or hydrogen). Among these are the metals in their reduced state, as it is termed; that is, the one in which they possess splendour, malleability, and ductility : sulphur, in its ordinary condition ; coal, when affording flame as it consumes ; phosphorus, when burning with blaze ;—among the metals, it is proper to observe, that potash, soda, ammoniac, lime, barytes, magnesia, alumine. and silex, are reckoned as well as the substances heretofore ranked as metals.

II. In the second class are contained minerals, as combined with oxygen. All metallic oxyds and acids, are comprehended in this division ; such as those of lead, iron, &c. as commonly received, and likewise, the alkaline salts and earths, argillaceous and siliceous earths, &c. in their states wherein they commonly exist, making the principal and solid materials of the globe. Modern science has demonstrated that these are chiefly metallic oxyds. The oxyds of carbone, come under this head ; including all the modifications of incombustible coal.

III. Minerals united to sulphur, make the third class; constituting all manner of pyrital combinations ; all sulphures and sulphurets ; and in short every one of the numerous combinations, denominated Ores, by intervention of brimstone.

IV. Amalgams and Alloys form the fourth class of mineral bodies. They comprehend all the mixtures of metallic substances with each other. Thus glass is an alloy of two metals, potash and flint; porcelaine and alloy of two metals, clay and flint ; stone-ware an alloy of clay, flint, and iron, under other modifications ; and the like applies to bricks, tiles, and other mixtures, heretofore deemed earths, but now shown to be metals. All the alloys of the metals, as usually understood, such as the mixtures of gold and silver, &c. with copper, mercury, &c. come under this head, of course.

V. Minerals, as related to acids, make a fifth class. Of these, the acetates of lead and copper, forming the saccharum saturni, and verdigris of the shops, are examples ; as are also the sulphates of iron, zinc, lime, barytes, soda, potash, and in short the intire section of the salia acido-metallica.

Such is the classification of minerals, proposed by Prof. M. to accommodate their manifold forms and species to the actual state of our knowledge. He has little doubt that sulphur ought to be considered as a metal:—consequently the 3d class comprehending the ores, will be merged in the 4th including the alloys. So when we shall know more about the constitution of acids, we shall probably, he says, transfer the subjects of the fifth class,—the acido-metallic salts, to the 2d, comprehending the metallic oxyds and acids.

Vol. I. 2 L

On this view of the matter, there will be but three classes of minerals, 1. their combinations with phlogiston : 2. their combinations with oxygen : and 3. their combinations with each other. And this arrangement will be the more satisfactory, inasmuch as carbone and phosphorus may be soon expected to take their places among the metals. And then, the carburets of iron, such as plumbago and steel ; and the phosphates of lime, such as the teeth and bones of animals, will occupy their appropriate places in the system ; the former going to the 4th class among the alloys, and the latter to the [3r]d among the oxydt.—Of this whole arrangement, the reader will find a striking corroboration from the experiments of that most ingenious and industrious chemist, who improves science with almost unexampled success, in the royal institution of London.

7. Botany is the next division of this course. It comprises all the vegetables which overspread the face of the earth, under two great aspects. 1. Their history as individuals of the animated creation, including their origin from seeds and germs, through the whole of their increase to their inflorescence and fructification, and the formation of seeds and germs again. This comprehends their anatomical, physiological, pathological, and economical characters and uses. 2. Their Classification ; which being explained according to the Sexual or Linnean arrangement, is too well understood to be enlarged upon in such a sketch as this.

8. In his Zoology, Prof. Mitchill follows the plan of Cuvier, as explained and detailed by Dumeril. The distribution of the animal race into the nine classes of Mammalia, birds, reptiles, fishes, molluscas, Crustacea, insects, worms, and zoophytes, seemed preferable to any other, because it embraces both their anatomical structure, and their external characters. For by thus seizing all the points of resemblance which the outward form and inward organization afford, animals of similar natures may be grouped together ; while by noting all the circumstances of discrimination, that external and internal marks present, the creatures of dissimilar configuration and appearance may be kept asunder. In this copious and fertile field of discussion, the human race is considered. He distributed the single species, man, as descended from the first original pair, into six races : 1. The Caucasian or European 2. Hyperborean or Laplander.—3. The Mongol or Tartar.—4. The American; that is the South American.—5. The Malay or Philippine.—and 6. The Ethiopian or Negro. As to the Aborigines of North America, he considers them as composed chiefly of two races : the Hyperborean, No. 2. which came in by the route of Greenland, and the arctic regions from the east :*and of the Tartar, No. 3. which entered by the way ol Alaska, from the west. And he supposes that the genuine American form and feature, are only to be found in the south.

9. The ninth and last division of this course, is termed Uranology. As in the former sections, terrestrial objects are treated of at great length ; so in this, it is intended to exhibit what is known of the Heavens—It is comprehended under three heads, to wit: 1. The history of the Copernican system ; comprehending the sun, the planets, satellites, asteroids, and comets: 2. An account of the sidereal system, or of the fixed stars which constitute the celestial firmament, of worlds, innumerable, distributed through immeasurable space, according to Herschell’s researches : and, 3. The way in which stars were, among the pastoral tribes of Asia, parcelled into constellations; and particularly how, for the purpose of tracing and describing in a clearer manner the sun’s course along the ecliptic, the zodiac was invented. Dr. Mitchill concludes with the history of the twelve signs; and professes his endeavour to infuse in his discourses as much as he possibly can of the spirit which animates the writings of Ray, Derham, Smellie, Fontenelle, Pluche, and Saint Pierre.



Observations on Phthisis Pulmonalis, or Consumption of the Lungs: communicated by Dr. Joseph Young, of New-York, to Dr. Mitchill.

IN my Treatise on Astronomy, Physiology, &c. where I treated on consumption, in page 170, I observed, that the medicines that were salutary in the morning were frequently injurious in the evenings and assigned as the cause, that consumptive patients are generally too cold in the morning, occasioned by profuse night sweats, and consequent debility; and art feverish in the evening : and recommended the use of warming balsamic remedies in the forenoon, and cooling remedies in the evening.

But finding this hint neglected, I think it incumbent on me to be more explicit in explaining the cause, why this should invariably be the case, in the advanced stages of the disease; as an accurate knowledge of the cause indicates what should be done to remove it, and thereby prevent its pernicious effects. But to effect this purpose, I must recur to physical principles. I conceive that I have proved in the 85 and 86, 96 and 97, and 116,117 pages of the Treatise, that fire, in its’ various combinations, and modifications, is the only physical or generative cause of heat, fluidity, motion, life, sensation, and muscular motion; for without fire, there could ‘ ‘not be any heat; and without heat, nothing would remain fluid; and without fluidity, there could be neither motion, life, nor sensation. The electric fluid is the most active, energetic modification of fire, and the universal physical agent, throughout our system. It is the chief ingredient in atmospheric air, and the sole cause of its elasticity and activity. But as no simple substance, alone, can generate motion, I conceive it can be demonstrated by experiments, that the electric fluid is composed of pure elementary fire and oxygene. When this elastic air is inspired, the electric part (which I shall hereafter call pyretos) pervades the lungs, and is immediately transmitted with the blood to the heart, which it invigorates to perform its constant action, as long as regular respiration is continued, (see page 144.) But if the inert part of the air which is expelled in expiration, be collected, it will extinguish both animal life and flame ; not because it has derived any poisonous quality from the lungs, but because it has been deprived of the pyretos, which gave it elasticity. When pure atmospheric air is inspired by an healthy vigorous person, the pyretos being excited into immediate action not only stimulates the heart and vascular system, but passes with the fluids to the remotest parts of the body, promoting circulation, and preventing cohesions, and obstructions, where the muscular force of the heart could have but little, if any influence ; (see page 75). Generating and diffusing heat, and promoting circulation in its passage, the pyretos passes off with the perspirable matter, reduced to an invisible vapour by heat and motion; so that it may be re-supplied at the next inspiration. See page 97, Treatise.

As long as this process is regularly performed, the person generally enjoys health.

But when the debilitated consumptive patient inspires this pure air, the pyretos cannot communicate a sufficient degree of power to the relaxed fibres of the heart, to propel the blood with sufficient velocity, to excite its energies to generate heat, or pass off in perspiration. It will therefore pass-on with the fluids in languid circulation, accumulating all the forenoon, until the patient takes a warm dinner, or a dish of warm tea, which soon excites and brings the whole accumulated stock into extreme active operation, which produces an agitation and heat above the sweating point. The inspissated fluids are now forced with velocity on the tender irritable lungs: the patient retires to bed, and has a violent fit of coughing, until the viscid matter is in some degree attenuated, and expelled by heat and motion. Being greatly fatigued.

With fever and coughing, he sinks into an unrefreshing slumber, which sometimes continues until day-light. During the latter part of this time, the circulation becomes very languid, and perspiration deficient, until the patient begins to stir and cough, which sets the almost dormant pyretos in very rapid motion. The pores being relaxed, and the viscid fluids in some degree attenuated, a most profuse debilitating sweat ensues, which sinks the unhappy patient lower. He at length arises; the cold and pressure of the air upon the external vessels on the surface propel the fluids inwards upon the tender irritable lungs, and produce a violent fit of coughing: and as the debility is daily increasing, the inspissation of the fluids, and the retention of both the pyretos and viscid matter must increase, in proportion to the diminution of heats and motion. Under these circumstances, it is obvious that the intention should be to defend the body from the action of the cool external air, all the forenoon ; and by the balsamic electuary and moderately warming diaphoretics, to support the heat of the body, and promote a moderate equable perspiration, which will both prevent the inspissations of the fluids, and the retention of the pyretos ; and thereby diminish the fever and cough in the evening. But to check it more effectually, the patient should begin about an hour before the accession of the fever, to take 30 or 40 drops of Spiritus Nitri dulcis in a strong warm tea of mullen flowers, sweetened with Spanish honey. A wine-glass-full of the tea may be drank warm every hour, without the spirit, and with it every third hour, until the fever begins to abate ; and then begin and take the bulk of an hazelnut of the balsamic electuary, every third or fourth hour; and take a wine-glass-full of a moderately .strong infusion of the bark of the wild allspice as frequently as it may be found necessary to promote the most gentle perspiration ; avoiding exposure to a current of cold air all the forenoon. If the cough is severe, cut open 5 or 6 good figs, and macerate them in a pint of boiling hot water, bruise them in the water, and sip it warm, frequently, to obtund the acrid stimulating matter, and promote expectoration. If the cough is very severe, a dose of paregoric elixir may be taken in warm mullen tea at bed-time ; but at no other lime, except in case of the greatest necessity. He should wear flannel shirts, and a plaster of Burgundy pitch of eight inches long, reaching from the nape of his neck along the spine between the shoulder blades, which should be renewed every eight days. The physician should always remember, that heat and motion are the sole causes of fluidity ; that heat renders metals fluid, and that cold can condense and consolidate mercury, so that it can be extended by the hammer. From hence it is evident, that the lymph and finer fluids may be inspissated by the cold, not only to form obstructions in the lungs, and produce a cough, but by obstructing the pores of the skin, to check perspiration, retain the pyretos (which should pass oft regularly) and thereby produce  a. fever. The salts of the blood are also retained until they acquire a destructive degree of acrimony, to irritate and corrode the lungs, and aggravate the fever. These salts, in the advanced stages of the disease, may be perceived at the bottom of the pot, like brick-dust. They sometimes become alkalescent; and by combining with the oily part of the fluids, they form a destructive soap, which deterges and carries off the viscous matter which lines the inside of the vessels, to defend them from the action of acrimonious fluids. I saw two cases of this kind in the winter of 1763. The urine frothed like strong soap-suds. I was then ignorant of the cause, but suspected from the appearance of the urine, that it was saponaceous. I put some of it into a small gallypot, and poured in a few drops of elixir of vitriol, with which it effervesced, and the froth disappeared in a few seconds. I then gave the patient 15 drops of the elix. in a wine-glass-full of spring water, every second hour, which soon reduced the urine to its natural appearance, and removed a very troublesome sensation of internal heat, and uncommon languor. But possibly, it may be objected that there is no such danger of the inspissation of the fluids as I apprehend, it having been ascertained, by introducing a thermometer into the armpit, that the heat of the body is nearly the same, both in hot and cold weather.

This is a fallacious experiment, and is but partially true, as it respects strong vigorous subjects, but absolutely [is true ], with respect to invalids. Their heat is frequently very unequally distributed. The face of an hysterical patient will frequently glow with heat, while her feet are intolerably cold. Cold dry elastic air contains more of the electric fire, in a given quantity, or space, than hot rarefied air ; and when it is inspired by a vigorous person, the pyretos is immediately excited into action, by a strong free circulation, diffusing heat in its passage to every part of the system.

But when this cool elastic air is inspired by a consumptive patient, its sudden rarefaction by the internal heat will overstretch the tender air vesicle of the lungs, and thereby increase the general debility. And for want of a free vigorous circulation, to give the pyretos the necessary degree of activity, it will remain almost dormant, in the remote parts of the system, as a magazine to furnish an ample supply of pyretic matter, to increase the heat and violence of the fever in the evening. Every remitting and intermitting fever is produced by an abatement of the natural degree of heat, and frequently with a rigor and convulsive shuddering, in which the fluids are inspissated, and the pyretos retained, which had been inspired, during the cold stage ; as it is evident, that it could not be passed off in perspiration, but is confined to the internal parts, until the hot fit commences. The inspissation of the fluids, and the retention of the pyretos, is the real cause why the heat and violence of the fever are proportioned to the degree and duration of the cold fit; unless the patient is weakened to such a degree, that the powers of reaction are extinct, in which case the patient expires in the cold fit. From hence it is evident, that that inspissation of the fluids, and the consequent retention of the pyretos is the immediate or proximate cause of all remitting and intermitting fevers; which most clearly indicates the propriety of maintaining the heat of the body, and promoting a moderate degree of perspiration during the intermission; and this is evidently more indispensably necessary in the hectic than in any other intermittent, on account of the tender condition of the lungs. If this mode of treatment is persisted in during the forenoon, it will mitigate the fever in the evening. I gained this knowledge by experience in the year 1763. The most successful method of curing Agues, elucidates and corroborates both my theory and practice ; for if we can increase the strength and support the natural heat during the intermission, we prevent the return of the cold fit and all the subsequent train of symptoms. (See page 107, to the 113, and the Peruvian Electuary 115.)

There is an erroneous opinion very generally received, concerning Consumption, to wit; that although it is a flattering disease, and frequently gives promising signs of recovery, it is nevertheless absolutely incurable. These opinions have been formed upon the following circumstances, to wit: many practitioners have not discriminated with sufficient accuracy between the different kinds of the diseases, nor have they attended to the different modes of treatment, that are necessary to be observed in the same kind of the disease, in different constitutions, ages and temperaments ; but too often treat their plethoric, emaciated, scorbutic, and scrofulous patients, in the same manner, with some nostrum or medicines that have succeeded, in curing some kind of consumption ; giving it morning, noon, and night, without any regard either to the stage of disease, or the heat or cold of the body. In the course of my practice I have met with two melancholy instances of the fatal effects of this indiscriminate mode of practice. I was called to visit a man who had caught a cold which produced a hoarse, dry-bound cough, a dry-skin, feverish heat and flushing of the cheeks. Under these circumstances, I had determined to take about eight ounces of blood from one ot his arms, and put him into a warm bath, cause him to inspire the warm vapour of an infusion of mullen flowers, and to take a wine-glass-full of it frequently, sweetened with honey, and the balsamic linctus, to promote expectoration. But his family being anxious to know my opinion, I told them the case required great care and judgment, to bring it to an happy issue: they were alarmed and wished to have a physician whom they named, called into consultation. When he came, a messenger was sent for me, but in the interim, he had strenuously recommended a decoction of the peruvian bark. When I arrived, he told me what he had proposed, and mentioned what he called a desperate case, in which it had succeeded, when other remedies had failed. I told him, that if the bark had ever been serviceable in any case, attended with a cough, it must have been in the case of a feeble phlegmatic patient, whose lungs were extremely relaxed, who expectorated great quantities of crude indigested matter without much difficulty and without any fever. He admitted that I had described the patient’s case exactly, but still insisted upon trying the effects of the decoction, a few days. I observed the case of Mr. L. was very different from that of the patient which he had mentioned; and that the decoction would certainly increase the fever and aggravate the cough, and risk the rupture of a blood-vessel in the lungs. I then told the patient the effects which the decoction would certainly produce. But the Doctor had expatiated so eloquently on the extraordinary virtues of the bark in consumptions, that the patient wished to try its effects, for a few days; in which time it exactly fulfilled what I had prognosticated, which added another victim to ignorance and obstinacy. The second case was so similar to this, that I conceive it needless to insert it, as he fell a victim to the same means prescribed by a different practitioner.