Treatise on the yellow fever; shewing its origin, cure and prevention. / By Joseph Browne.

A TREATISE, &c.

THE prevalance of the Yellow Fever, as it is general|ly denominated, in many of the sea port towns of Ame|ca, has naturally excited the attention of every class of citizens, and drawn forth observations and remarks from some of our most respectable philosophic and medical characters, to whom much praise are due; the subject however does not appear to be exhausted, it is yet sus|ceptible of improvement. I shall endeavor to place it in a new point of view, in as concise a manner as I am able. The attempt may be the means of calling forth the observations of others better qualified to illustrate the subject. I regret that neither my abilities or situation enable me to do it that justice which it certainly deserves.

The origin of the disease has been variously accounted for, and with some degree of warmth by those who con|sider it as of foreign birth, with a view to exculpate their country from the stigma which attaches to a city that generates so destructive a calamity. However praise|worthy it may be to endeavour to exonerate any place from so soul an imputation, yet we ought to be extremely cau|tious of crediting a belief in its foreign origin, unless sup|ported by incontestible facts, because it may lull us into a fatal security, and induce us to neglect those means of preservation, which a contrary opinion puts us in possessi|on of. I believe it most just, and at any rate most saluta|ry, to consider the yellow fever as endemial to many of

our cities; because the same means that would prevent its rise here, are precisely those that retard and remove its pestilential effects when imported, to wit, cleanliness and good air.

The great improvements that have been made within a few years in chemistry, form a new era in that science, which will most extensively influence the practise of me|dicine, particularly in the treatment of the disease in ques|tion, and others of similar nature, though different in de|gree, viz, the plague, West-India, Bengal, camp, goal fever, marsh fever, bilious fever, autumnal, remitting, and most probably the common intermittent.

As I do not exclusively address myself to men of sci|ence, I shall endeavour to divest my observations as much as possible of technical terms, that the plain citizen, whose health is his greatest good, may comprehend some|thing of the nature of the disease, and of course will be more cheerfully inclined to contribute his mite towards preventing its origin and removing its effects.

I propose to consider the subject under three heads or questions.

• 1st. What is the cause of the yellow fever?
• 2d. What is the best mode of treating it?
• 3dly. What are the surest means of preventing it?

In considering the first question we must examine the nature of the air we breath, or atmospheric air, and the operation breathing effectuates on the animal machine. By the assiduous application, and unremitted attention of several eminent philosophers and chemists, among whom the names of Hales, Black, Macbride, Priestly, Cavendish, Lavoiseir, Foureroy, Berthollet, Chaptal and De Mor|veau will not be forgotten while science is recorded. We are now able to analyse the atmospheric air, which in|stead of being a simple element, is found to be a chemi|cal

compound, a knowledge of whose principles becomes the more interesting, as nature has made them her prin|cipal agents in most of her operations; which may be considered as her grand laboratory, from which the seeds and pabulum of animal and vegetable life are derived, and to which their subsequent decomposition returns the same principles which before were extracted. The physical properties of atmospherical air are fluidity, invisibility, gravity, elasticity, compressibility, and negation of smell. though foetid and odorant substances sometimes affect our organs, they are to be attributed to the extraneous bodies mixed and floating in the air, which is itself perfectly inodorous.

From the most conclusive and satisfactory experi|ments of Priestly and Lavoisier, it is ascertained, that the atmospheric air will not, in its totality, maintain animal life, or promote combustion; the proportion of air that answers either of these purposes, compared with the atmospherical air, is only as 28 is to 100, which has been called by the French academicians oxigenous gas, or oxigen; the residue, or 72-100 of the atmospheri|cal air has been called azote, or nitrogene.(a) 1.1

It has become necessary, that a revolution in the sci|ence of chemistry should be attended with a similar re|volution in its language; for it is impossible to retain a vicious nomenclature when the science becomes en|lightened, extended, and simplified: the words used should always identify the fact, that the knowledge of the one should always lead to a knowledge of the other. I am sorry here to be obliged to criticize on some of the words that have been adopted, because they do not carry the unequivocal appropriate ideas which we have

a right to expect, when an innovation is introduced: the word oxigen is derived from the greek, and signifies the begetter of acid, or the basis of acidity; so far the word perfectly corresponds with the fact, and probably it is from this principle only, that it is of such infinite and indispensable importance to animal life: but as it is the essence of life, this circumstance gives it a priority of claim to stand its God-father; I shall therefore sub|stitute for it the term animal vital air; this indeed does not designate all its qualities, nor is it necessary that it should; but it defines, with sufficient correctness, its great leading trait—the supporter of animal life: the words azote, or nitrogene, are more exceptionable than oxigen; azote is likewise derived from the Greek, and signifies without life, which is just as descriptive of the halter or the guillotine, as air: nitrogene is likewise of Grecian origin, and is meant to shew, that it is the basis of nitre; that it is so, I readily admit, but I am not disposed to believe, that this trifling circum|stance was of sufficient consequence to give a name to the sine qua non of vegetable life; I think it ought ra|ther to have been called vegetable vital air—a name which I shall take the liberty to adopt; for it is a fact as well ascertained, as it is possible for a chemical fact to be, that in this air plants live and vegetate, without it they die: animal vital air is more ponderous than at|mospheric air, as 1000 is to 1103; vegetable vital air, on the contrary, is lighter, as 985 is to 1000; these two airs, in the proportion of 28 of the former to 72 of the latter, forms the atmospherical air, which is a che|mical compound, and is about 850 times lighter than water.

It is an axiom in chemistry, that all substances in na|ture, whether in a simple or compound state, would invariably continue in that same state, unless for a prin|ciple which pervades all creation, and is called electric attraction, or affinity of composition: unions formed from this cause, are more or less perfect, in proportion

as their substances have a greater or less affinity for each other. I shall exemplify my meaning by a substance with which we are most of us acquainted, to wit, nitre, or saltpetre(a) 1.2, which is compounded of nitric acid(b) 1.3, or what is commonly called aqua fortis, and potash: now it has been discovered that the sulphuric acid, or as it is commonly called, oil of vitriol, has a greater af|finity for potash than the nitric acid has; consequently, by placing these substances in a certain temperature to|gether, a decomposition of the nitre takes place—the nitric acid is discharged, and a new union between the potash and sulphuric acid is formed, which is called the sulphat of potash. Nitre may likewise be decom|posed in another way: it is known that Barytes, or the Terra Ponderosa, has a greater affinity for the nitric acid than what potash has—let them therefore be placed conveniently together, and a decomposition of the nitric is produced, the nitrate of Barytes is formed, and the potash set at liberty.

On this principle, when any portion of atmospheric air comes in contact with any substance that has a great|er affinity with either of its component parts, than these parts have for each other, a decomposition of this por|tion takes place, and a new union is formed.

It is a primordial and invariable law of nature, that all and every part of creation, as well animate as inani|mate, should be in a constant state of renovation, thro' a continual circulation of decompositions, and successive generations. The wonderful discoveries of the che|mists

point out to us in the most positive manner, that the absolute existence of animals and vegetables depends on a mutual reciprocity of each others wants; animals absorb animal vital air, and emit vegetable vital air; on the contrary, vegetables absorb vegetable vital air, and emit animal vital air; the leaves are the medium through which this exchange is made by plants; the lungs and the excretory pores, on the surface of the bo|dy, are destined to this purpose in animals—or, in other words, vegetables, when in a state of active existence, have a greater affinity for vegetable vital air, than what animal vital air has, consequently the vegetable vital air of that part of the atmospheric air which comes in con|tact with vegetables in a state of verdure, quits its con|nection with the animal vital air, and attaches itself to the plant; on the contrary, the animal vital air of the atmosphere has a greater affinity for the blood of animals than it has for vegetable vital air; whenever, therefore, it comes in close or near contact with this substance, a new union is formed: it is, however, not to be under|stood as forming an union with the blood on the same principles as the sulphuric acid does with the potash, previously combined with the nitric acid, because, in this case, a violent effervescence takes place, in dislodg|ing the nitric acid, but this union may be more aptly compared to that which takes place between quick lime and fixed air, or carbonic acid, for two reasons—in the first place, the heat that is generated in the lime from this union, is perfectly similar to the heat of animals, which is acquired by the absorption and condensation of animal vital air(a) 1.4: in the second place, the lime is

more or less acrid in proportion as it is less or more sa|turated with its appropriate acid: on the same princi|ples the blood of a living animal is less or more acrid, or fit for the purposes of life, as it is less or more neu|tralized with animal vital air, which is the basis of aci|dity; the blood itself can never shew any great degree of acridity or corrosiveness, because it would destroy ani|mal life before it arrives at this state; but that the se|cretions from the blood may, and sometimes do become very considerably acrid, is most certain—particularly the bile which is always eminently affected in all the diseas|es in question; the bile, in its healthy state, is very considerably alkaline, although secreted from blood per|fectly neutralized—at least, as much as venous blood can be, for the bile is not secreted from artereal blood; but when the blood is not, from a deficiency of animal vital air, sufficiently neutralized, it is in this case easy to con|ceive that the bile secreted from such blood will be in excess, and must possess a quality verging towards an acrid state—which, according to the deficiency of ani|mal vital air, and the heat of the season, as we shall by and by see, may produce a disease of slight affection on|ly—as the fever and ague, or of the most virulent kind, the plague itself.

Every animal is furnished with lungs, or something corresponding thereto, through which the blood in con|stant succession passes, by which means it is brought in close contact with the atmospheric air, and from which we now know it absorbs that part of it which we call animal vital air; after the atmospheric air has thus been respired, it loses its property of supporting the lives of other animals: when an animal has died in this respired air, and another is substituted to the first, it perishes in|stantly, and in its first effort to respire: it should seem, however, that animals may, by habit, become capable, to a certain point, of breathing impure air.

The phoenomena of respiration are but lately ascertained

though from the time of Hippocrates it has been admit|ted, that in the air resides a principle necessary to life, which by him was called the pabulum vitae; this idea was connected with no hypothesis; systems the most vague and void of all foundations, have at different times been held up; at one time considering the air as a stimulus in the lungs, which kept up the circulation; at another the lungs were considered as a bellows to cool the body, heated by a thousand imaginary causes. Physiologists of the pre|sent day seem to consider them as the outlets of certain putrid effluviae, which would corrupt the living body in the same manner that it produces corruption in those that are dead. The rationale is extremely against such a theory; for is it conceiveable that the same viseus can be at the same moment performing two functions diametri|cally opposite to each other? that of absorbing and se|creting through the same vessels, unless they suppose it similar to elective attraction, as mentioned before, where potash having a greater affinity for the sulphuric acid than for the nitric acid, discharges this acid with which it was previously combined. But there is no sort of ana|logy in this case, for the matter discharged from the lungs instead of being an acid, is more of an alkaline nature, mixed with carbon; which I think is very sufficiently ac|counted for, on the following principles: In examining the construction of lungs, we find them furnished with two setts of vessels, a larger and a smaller; through the larger the whole of the blood of the system is constantly transmitted, for the exclusive purpose of attracting ani|mal vital air from the atmosphere. The smaller sett is appropriated to the exclusive support of the lungs them|selves, and to furnish a considerable secretion, necessary to lubricate a part which is in such constant motion, to faci|litate the return of the respired air in the atmosphere; and to 〈◊〉〈◊〉 the acrimony of any heterogeneous matter with which the atmosphere is frequently charged. This secretion will sufficiently account for the great quantity of moisture discharged in expiration. The excretory pores distributed over the whole surface of the body are

sufficiently competent to discharge this duty which has been assigned to the lungs by our modern physiologists.

It has been long an established principle among phy|sicians, that all animals have a constant tendency to pu|trefaction; but it has been reserved for our own times, to point out the cause that is capable of correcting this tendency. Borehave in his aphorisms, §. 83, says,

in|sects, fishes, amphibious creatures, birds, beasts of all kinds, and even men of their own nature, constantly in|cline to putrefaction, but never turn acid

Van Swe|ten in his commentaries on this aphorism says,

all the known animals (except a few juiceless insects, for moist|ure is required in putrefaction, and the parts of animals never putrefy if they are dried) putrefy, if exposed to the heat of an air, which shall cause the liquid to rise in the Farenheitian thermometer to any degree between the 32d and the 92d. The greater the heat is within this limit, so much the sooner for the most part will the putrefaction begin, for beyond the 92d degree the heat rather drys up all moisture, and so hinders putre|faction, and the nearer the descending heat approaches to a like degree of coldness with that of ice, the slow|er the putrefaction comes on. In fishes it generally comes on very soon, more slowly in other animals. Nor does it appear by any experiment, that the parts of animals have ever degenerated of themselves into an acid; this therefore may be taken for a general rule.

It appears therefore, that one of the great charactaristic differences between the animal and vegetable kingdoms, is this, that animals constantly tend to an alkaline or pu|trescent state, and vegetables to that of acidity. We have seen before that the two kingdoms are constantly mutual|ly correcting each others morbid tendency, through the medium of the atmosphere.

From these premises it is easy to conceive, that when the atmospherical air in any particular place, is not from any cause sufficiently replete with animal vital air, this

grand corrector of putrescency, that then the animals re|siding within that district must, more or less, become dis|eased, according to their previous putrescent tendency; for Boerhave observes in his §. 84,

that the antecedent causes of this putrefaction, are feeding upon animal food, except the milk of grazing cattle, especially upon insects, fishes, birds of prey, alkalessent vegetables; a fullness either of good blood, or of blood acceding to|wards putrefaction; the strength of the vessels, viscera, bile, stagnation, or too much agitation, through the animal motion either growing languid, or being raised too high, great heat affecting the body frequently and long.

This aphorism in some measure explains why a deficiency of animal vital air does not equally affect all those who are exposed to it. Galen likewise lays it down as a rule,

that it is always necessary to remember, that no cause can effect without a predisposition of the body, otherwise all who are exposed to the rays of a summer sun, would be seized with fevers, as well as those who use too much exercise, are passionate or grieved. Moreover all would fall sick during the dog days, or die of the plague.

M. Chaptal has taken notice of a fact which is of some importance, and deserves to be related here; it is, that "frugivorous animals vitiate the air less than carnivorous animals," which may be account|ed for in this way, that frugivorous animals having less ten|dency to putrefaction than carnivorous animals, they re|quire less animal vital air to correct that disposition; for instance, an animal fed altogether on vegetables, would be able to absorb a sufficient quantity of animal vital air to prevent putrefaction, out of an atmosphere that contained only 20 per cent of this principle, whereas an animal fed altogether on animal food, with a less quantity than 25 per cent, would probably be affected with a putrid or bi|lious fever.

A diminution of animal vital air, at a season when the thermometer is at or below 32d. may produce no bad effect; but the same diminution continuing, and

the heat increasing, a fever and ague may be occasioned by it: a still greater increase of heat may occasion a dysen|tery, a further diminution of animal vital air, and an increase of heat, the yellow fever, or even the plague it|self may be generated. The Plague, therefore, can probably never originate in a cold climate, but it may, when carried here, exert its pestilential influence, by producing an increased decomposition of animal matter, and of course, generating much vegetable vital air, with which the atmosphere becomes surcharged, whereby the animal vital air is so diminished, that the natural tenden|cy to putrefaction cannot be sufficiently corrected; con|sequently, the disease goes on rapidly, increasing its dreadful influence, until one of the two causes intervenes to stop its progress—either a less disposition to putrefac|tion, or an increase of animal vital air.

I shall now adduce a few traits to corroborate this sys|tem: Forestus(a) 1.5 relates, that a large fish of the whale kind, of immense bulk, ran ashore on the Dutch coast, nor could again reach the sea, notwithstanding its utmost efforts, and at length died on the sands; numerous spe|culators ran thither from every part. Forestus himself was present. The neighbouring inhabitants, not being able to remove the dead fish, on account of its prodigi|ous bulk, and neglecting immediately to divide the car|cass into small pieces, the whole putrefied, and infected the country with a horrid rancid stench, in consequence of which, a pestilential fever broke out in the district of Egmont, and the adjacent parts, that carried off great numbers. This case goes merely to one fact, to shew that putrid animal substances, in a state of decompositi|on, are alone sufficient to generate pestilential fevers, by supersaturating the atmosphere with vegetable vital air.

The next case I shall relate is much in point, and is recorded by Sir Michael Foster(a) 1.6: a Mr. Clarke was brought to his trial at the Old Bayley sessions, in April, 1750—it being a case of great expectation, the court and all the passages to it were extremely crowded; the weather was hotter than is usual at that time of the year; many people who were in court were sensibly affect|ed with a noisome smell, and it appeared soon afterwards, upon an enquiry ordered by the court of Aldermen, that the whole prison of Newgate, and all the passages leading thence into the court, were in a very filthy condition, and had long been so. What made these circumstances be at all attended to, was, that within a week, or ten days at the most, after the sessions, many people who were present at Mr. Clarke's tryal, were seized with a fever of the malignant kind, and few who were seized recovered. The symptoms were much alike in all the patients; and in less than three weeks, the distemper entirely ceased. At the time this disaster happened, there was no sickness in the gaol more than is usual in such places; the circumstance, that distinguisheth this from most of the cases of the like kind which we have heard of, suggests a very proper caution, not to presume too far upon the health of the gaol, barely be|cause the gaol fever is not among the prisoners; for, without doubt, if the points of cleanliness and free air have been greatly neglected, the putrid effluvia which the prisoners bring with them in their cloaths, or other|wise, especially where too many are brought into a crowded court together, may have fatal effects on peo|ple who are accustomed to breath better air: though the poor wretches, who in some measure are habituated to the fumes of a prison, may not always be sensible of great inconveniencies from them. The persons of chief note who were in the court at this time, and died of the

fever, were Sir Samuel Pennant, lord mayor for that year, Sir Thomas Abny, one of the justices of the com|mon pleas; Charles Clarke, Esq. one of the barons of the exchequer, and Sir Daniel Lambert, one of the aldermen of London: of less note, a gentleman of the bar, two or three students, one of the under sheriffs, an officer of chief justice Lee, who attended his lordship in court at that time, several gentlemen of the jury on the Middlesex side, and about fifty other persons, whom business or curiosity had brought thither.

I have related this case rather lengthily, with a view to make a few observations on it: it shews that a malig|nant fever may, like the last case, arise from putrid of|fensive matter, and a confined air: it also shews that the prisoners, who contributed largely to generate the disease, did themselves escape its destructive influence, by being in some measure habituated to it; for that na|ture can, and does by degrees assimilate our constitutions to varieties of climate and atmospherical changes, are facts that constantly occur, without which the West and East Indies, the coast of Guinea, and the Low Coun|tries of the southern States, would be uninhabited by Europeans, or the inhabitants of the more northern and elevated parts of America. It is probable also, from low diet, the natural tendency of the prisoners to putre|faction was less than that of the high fed judges, law+yers, and Middlesex jurymen, who were victims to the disease.

This case likewise furnishes us with another fact of some importance: it states, that the disease commenced in April, and in about six weeks, that is the beginning of June, disappeared. Now, from what has been before observed, in the month of June, the natural tendency to putrefaction, from the increase of heat, must have been much more powerful than it was in the month of April; of course, the disease, instead of entirely ceasing, ought to have increased rapidly; why it did not, I shall now

endeavour to account. In the month of April, in nor|thern climates, vegetation is still dormant, consequently the atmospherical air must then be surcharged with vege|table vital air: as the summer advances, this vegetable vital air will be in great demand, for the nutriment of plants; of course, not only a diminution of it takes place, from being absorbed by plants, but a great quan|tity of animal vital air is generated by them, and thrown into the atmosphere, from whence it will be absorbed by animals, to whom it is a sine qua non.

Plants not only have the faculty of emptying into the atmosphere animal vital air, by perspiration, but they possess likewise the means of throwing into circulation an immense quantity from another source, to wit, from rain and dews: to understand this aright, it is necessary to premise, that from the best authenticated facts, wa|ter, instead of being a pure element, is discovered to be compounded of two species of air, viz. animal vital air, and inflammable air, or, as it has been called, hydro|gene, in the proportion of 85 of the former, and 15 of the latter: now it is well known that plants have a great|er affinity for hydrogene, than animal vital air has; of consequence, when water or dew fall on the leaves of plants, the hydrogene is absorbed, and the water decom|posed; therefore the animal vital air must be thrown in|to the atmosphere; the heat and light of the sun greatly facilitates this operation: one square inch of water contains near nine hundred square inches of animal vital air.

This is by no means a solitary case of a malignant fe|ver ceasing in the heat of summer; the history of the plague furnishes us with a great many: I shall select two or three. When the plague raged at Aleppo, and in the beginning of July, the hottest season of the year came on, the disease remarkably diminished; and towards the end of

the same month entirely ceased.(a) 1.7 In general it has been observed in Aleppo, that the plague always ceases in the hottest season of the year, as manifestly appears from the accounts of several years in which the plague raged.(b) 1.8 In the year 1738 and 1739 the plague raged at Oczakow; in each year it broke out in April, raged till the 12th of June, after which day it decreased apace; and wholly ceased in September: it returned again in the month of February in the following year, and was totally extin|guished in the month of July.(c) 1.9

I have thus shewn that malignant diseases may arise from a combination of two causes—heat and a deficiency of animal vital air. That the yellow fever which has rava|ged many of our cities, did originate among ourselves, I will not undertake to say, but that the heat of our cli|mate, the filth of the streets, the putrefaction in the docks, added to the inhabitants living on so much animal food, are not only sufficient to give rise to it, but full activity, cannot be doubted; and it is, in my opinion, a matter of no importance to determine whether the disorder was im|ported or not, since we have adopted it, by making it so welcome.

I might have quoted a variety of other facts to substan|tiate the same principles, particularly the jail fever at the black assizes at Oxford, the case of the unfortunate prisoners confined in the black hole at Calcutta by the Nabob Surajeddoullah, &c. but it would have been nearly a repetition of the same effects, produced by similar caus|es. I shall now proceed to consider what is the best mode of treating the yellow fever.

It is a great point gained always, when a physician can indubitably fix on the cause of a disorder; his efforts to remove it will then be grounded on a rational practice. The yellow fever I have said, arises from a combination of two causes, a certain degree of heat, and a deficiency of animal vital air, whereby the circulating fluids acquire a strong tendency to putrefaction. Of all the secretions made from the blood, none so readily feel the influence of putridity as the bile, whose use appears to be, from its alkalessent nature, to render the oily parts of the food miscible with the aqueous in the duodenum; which is the intestine next below the stomach, in which the food has been previously digested, for the bile is never discharged into the stomach in an healthy state, it can get there on|ly by vomiting, or some such effect; the idea of the sto|mach being overcharged with bile is an error.

The progressive effects of heat above 32d of Fahren|heit's thermometer, and a deficiency of animal vital air below 27 per cent. of the atmosphere will be as follows: the blood by having too little of the principle of acidity in it, secretes bile in too large a quantity, consequently instead of simply converting the food to a bland chyle, its excess will occasion a fever and ague, or a dierrhoea; when the primary causes above mentioned are increased in degree, the bile not only becomes increased in quantity, but its quality also is materially affected; it acquires a tendency to throw the food into a putrefactive fermentation, which becomes a rotten sanies, and an excoriation of the bow|els takes place, which constitutes dysentery; or when in|sensible perspiration happens to be deficient, a fever will be induced, and will be known by the name of Yellow Fever, bilious fever, camp fever, goal fever, &c. accor|ding to the place and particular accompanying circum|stances; a further increase of one or both of the predis|posing causes will occasion the plague.

In the Yellow Fever therefore, the primary object of the physician will be as soon as possible to empty the con|tents of the bowels, and to throw into the atmospheric

air an additional quantity of animal vital air, which is easily procured by the decomposition of nitre. We have already seen, that nitre is a neutral salt, composed of potash and the nitric acid, and that sulphuric acid has a greater affinity for potash than the nitric acid has; consequently, by being mixed together, the nitric acid will be discharged. A simple and ready method is this—in a chafing dish of coals, place a large gallypot nearly filled with sand, in the sand place a smaller gallypot about half full of sulphuric acid, into which gra|dually throw nitre in powder; an effervescence immedi|ately commences, which is the separation of the nitric acid; the fumes as they immediately arise from the pot are acid and corrosive, and should be avoided as not being respi|rable until more diluted in the air. This method was lately very successfully used at Sheerness in England, on board the ship Union, in which a malignant fever had for a considerable time raged with some violence, but by the use of this means was entirely removed: It was suggest|ed by Dr. Carmichael Smith, for which he was after|wards made (it is said) physician extraordinary to the King. The principles on which he recommended it were these, he imagined that the contagion arising from the malignant fever was occasioned by certain alkaline effluvia, discharged from the bodies of the patients, that by throwing into the air the nitric acid, to be attracted by those effluvia they were to be neutralized, and of course rendered inert. How far such an opinion can be sup|ported on philosophical principles, I shall not undertake to discuss, for having determined not to find fault with the opinions of others in giving my own, I shall not throw the gauntlet to the doctor. Nitre may be decompound|ed by heat only, which is probably the best method of doing it, as it respects a complete separation of its princi|ples, by which means it will be more susceptible of new combinations. It must be put in a retort and kept in a red heat for some time before the gas begins to separate. In hospitals, by means of tubes, the gas may be thrown into any ward; but in private houses the use of it would

become more difficult, unless carried there, which may ea|sily be done in a machine to be mentioned by and by. One pound of nitre contains about 12,000 cubic inches of animal vital air, which is about 1-5 of its weight. Animal vital air may also be procured in large quantities and with great facility, by pouring sulphuric acid on man|ganese in powder, the vessel containing the manganese should be placed on a chasing dish of coals.

The disease in the beginning is confined to the fluids only, it is of great importance therefore, to diminish their quantity, and repair the loss if possible with those of a more accessent kind, obtained from vegetables only. On this principle, bleeding in considerable quantities is a practice well founded, and which has been recommend|ed by Galen, Botalli, Sydenham, Van Sweiten, and many others of great respectibility. There is a point however beyond which this liquid of life cannot be drawn with impunity, unless the loss could be immediately re|paired, which can be done in one or two ways only: the first and most natural is by food, but this unfortunately is very difficult to be done, as the patient generally loaths all food, but a small renovation can be expected from this source. From the other way great expections were once formed, though it is much to be regretted were soon a|bandoned; I mean the transfusing of good sound blood from the veins of an healthy person or some animal into the veins of the patient who loses a proportionate quan|tity of his bad blood. That the operation has been fre|quently performed, the books tell us. When the disease like the Yellow fever is confined to the circulating juices, the theory is rational, and deserves to be considered; I give it merely as a hint.

I have already observed, that vegetable vital air is gene|rated by animals, and expelled from their bodies by means of excretory vessels on their surfaces, it is in other words a decomposition of animal matter which is discharged from the body not only as useless but pernicious. In a

healthy state of the blood a retention of this matter will occasion a variety of very serious evils; but in a diseased state, and particularly of the one under consideration, it is of the utmost importance that every facility be given to its outlet; whatever then will contribute to promote perspiration should be freely applied, and assiduously per|severed in.

I have mentioned before, that vegetable air is in a small degree lighter than animal vital air; this is to be under|stood in a pure uncombined state, in which case the ve|getable vital air would naturally tend to elevate itself above the animal vital air, but the affinity they have for each other, although it be not a strong one, will naturally in|cline them to an union, which is greatly promoted by agitation. There is another circumstance respecting airs or gazes which should not be forgotten, which is, that their weight depends altogether on the caloric or heat and moisture with which they are combined; wa|ter for instance deprived of its caloric becomes ice, give it an additional quantity of caloric and it becomes vapour or gas. Vegetable vital air therefore, discharged from an animal by perspiration, being inveloped in a considera|ble humidity, will not ascend from the body with that faci|lity which it would otherwise be capable of, consequently the body becomes encircled with an atmosphere greatly sur|charged with vegetable vital air, which probably in this state may be capable of being taken into the body again by means of the absorbent vessels; to prevent which and to give full operation to new air that may be thrown into the sick room, the vitiated air should be constantly remo|ved; it may be done by throwing a current of air on and near the bed, but which may be attended with the bad ef|fect of checking perspiration, which should be carefully avoided, for the reasons already assigned. The known compressibility of airs, suggests the propriety of using the following described machine, which may be called an abstractor

[figure]

• A A tubulated metallic box of any dimensions, say 6 inches square.
• B A value in the tubulure.
• C A gun barrel screwed to the tubulure.
• D A piston to be worked by.
• E The handle.
• F A flexible tube of any conveni|ent length, inserted into the gun barrel at C, by which means, as the piston is worked, the air enters the flexible tube at G, and is forced into the box through the valve.

It is evident therefore, that the air may be extracted from any place wherever the point G of the flexible tube can be applied, either on the bed, under the bed, or in the bed itself, without in the least incommoding the pa|tient. A box of 6 inches square contains 216 inches; now it is a fact well known, that air may be compressed in|to a volume of 128 times less than what it commonly oc|cupies; consequently a box of the above dimentions may be made to contain 27,648 square inches of air, which may be taken to the top of the house and discharged, by drawing out the piston and forcing the valve open with an iron rod. This operation may be repeated as often as it may be thought necessary, by which simple contrivance the air of the room may be kept perfectly sweet without endangering a check to the perspiration. This is the in|strument I had reference to, when speaking of transport|ing animal vital air from any place where it may be con|veniently manufactured, to the chamber or bed of the pa|tient. To the retort containing the nitre to be decomposed, or to the vessel containing the manganese and sulphuric acid, let there be affixed and well luted, a large tubula|ted

matrass, to the tube of which let the tube of the ab|stractor be affixed; as the gas rises in the matrass a few strokes of the piston will drive it into the box, which when filled may be carried to the bed of the patient and there discharged in the manner already directed.

The atmosphere contains, as I have already mention|ed in a note, by Mr. Lavoisier's estimates, about one per cent of carbonic acid, a gas more generally distributed throughout the animal, vegetable and mineral kingdoms than any we are acquainted with; it is disengaged in this form by the putrefaction of animal substances, the decom|position of vegetables heaped together, the fermentation of wine, beer, cyder, &c. by all calcareous substances, when exposed to a strong heat, &c. in this acid neither animals nor vegetables can exist; an animal immersed in it almost instantly dies. I do not however consider this air as deliterious or poisonous, as it is generally understood, but an animal dies in it nearly on the same principles that it would do if immersed in water, that is from a to|tal deficiency of animal vital air; consequently a sudden stop is put to the circulation. The lungs of the drowned person are collapsed; if inflated again in a reasonable time with common air, he may be reanimated. The lungs of a person suffocated with carbonic acid remain inflated with this acid; of course it becomes more difficult to re|animate him, because this air must be first extracted.

The weight of carbonic acid, compared with common air, according to Mr. Kirwan, is as 45 to 68 nearly; from this circumstance, it naturally subsides to, and occupies the lowest places, from whence it may be very readily removed, by the application of a quantity of quick lime, with which substance it has a great affini|ty: 1200 pounds of quick lime will absorb about 800 pounds of carbonic acid, to convert it into slacked lime; for this reason, then, a quantity of quick lime should always be kept near or under the beds of patients in the yellow fever: its application would be attended with

another advantage—it absorbs also a great quantity of, humidity, which is apt to prevail in such rooms, and which should never be attempted to be removed by fire, as fire, by its combustion, absorbs animal vital air in great quantities: the carbonic acid has been recom|mended as an antiseptic remedy, but this fact wants con|firmation.

Having thus shewn the cause of yellow fever, and the best mode of treating it, I shall now proceed to the third question, and point out the surest means of pre|venting it. After saying that fifth may generate the dis|ease, it can scarcely be necessary to say, that cleanliness in a great measure will prevent it: an invariable attenti|on must certainly be paid to this object, as well in per|sons and houses, as the streets and docks; for it should never be out of my mind, that heat and moisture are the two great agents that constantly incline all animal sub|stances to decomposition, which then form a gas of ex|treme expansibility, occupying the place in the atmos|phere of a principle that is of the last importance to ani|mal life. It may happen, notwithstanding very pru|dent care, that an excess of vegetable vital air may pre|dominate in the atmosphere; you will then ask what is to be done to prevent it? plant trees in every street—trees, as has been remarked before, not only absorb ve|getable vital air, but generate, in large quantities, ani|mal vital air, and decompose water. The animal and vegetable kingdoms are constantly labouring for each other, and by this admirable reciprocity of service, the atmosphere is constantly changing, and an equilibrium maintained between its constituent principles.

Hot, dry, and stagnating air, has been observed the forerunner of pestilential diseases; that they should be so, from the foregoing theory, is inevitable, for the fol|lowing reasons: heat, by dilating the texture of ani|mals, increases their natural tendency to putrefaction: drowth diminishes the requisite proportion of animal

vital air in the atmosphere, by not furnishing the requi|site quantity of water to be decomposed by the leaves of vegetables (for water, by its decomposition, purifies the atmosphere, by pouring into it streams of animal vital air) consequently this air, by stagnation, becomes overcharged with vegetable vital air, and not being agi|tated and removed by gentle breezes, pestilential diseases begin their destructive career; whenever these circum|stances, in a greater or lesser degree, shall therefore oc|cur in a city, diseases of a more or less serious aspect will be the consequence; but by planting the streets with trees, and procuring a supply of water to sprinkle the streets and trees occasionally in the heat of the day, it is more than probable the yellow fever will never there|after depopulate the city.

The local situation of New York is equal, if not su|perior to any commercial city in America, probably in the world; it possesses almost every thing but one, to render it the jealousy of nations: when we see the ele|gance and numbers of her public buildings, the splendor of her equipages, and the extravagance of her citizens, we are astonished that this one thing, which is easily procureable, should be wanting—that is, a plentiful supply of good fresh water, particularly when it is known that this supply may be had for about half the price that is now paid for a scanty supply of tub water. The whole river Brunks, if it were necessary, may be turned through the streets of New York: nothing could possibly tend so much to blend the utile dulci as this; it would, in an eminent degree, secure the health and wealth of the city: it would, in fact, be its protector against those two great scourges of cities—fire and pesti|lence.

I have before remarked. that animals living on vege|table food, do not destroy so much animal vital air as those that live on flesh; of course, they do not want so much; it is therefore an object of considerable import|ance,

to abstain, during the dog days, as much as possi|ble from the use of flesh meats, and particularly fish: abstain also from the use of much spirituous liquors, they tend to heat the blood, without correcting its pu|trid tendency; on the contrary, beer, cyder, and wines, are necessary: abstain likewise from crowded houses, particularly theatres, whose air is not only contamina|ted by the number of people breathing it, but the can|dles, by their combustion, tend rapidly to render it un|fit for the support of animal life. It would be a very good practice, and not attended with much expence, if the proprietors of houses of this description, were to cause a quantity of nitre to be decomposed in them when crowded.

The practice of burying in church yards and vaults in New-York, has been I fear too long sanctioned by cus|tom, to be affected by any feeble efforts of mine; but the accidents that have happened in many other places from a similar practice, will I hope be a sufficient apology for speaking a few words on this subject. According to Mr. Petit, a body buried four feet under ground without a coffin, will be from three to four years before it be quite decompounded, if buried deeper, the time will be longer; if buried in a coffin, it will require ten years to produce the same effect. The quantity of vegetable vital air constantly emitting from bodies previous to the above periods is great, consequently combining with an excess of vegetable vital air already in the atmosphere, may be the means of very serious mischief; the risk however from those causes is by no means so great as from the opening of vaults in cities, the most serious evils have frequently arisen from this cause. Burials then should be at some distance from a city; I have no objection that the inanimate bodies should still be consigned to the purveyance of the priests, it is in many places a perquisite of the church; common decency will point out the proper interment; if you please the burial service for the dead may still he said over it, the living may benefit from it. It appears to me how|ever,

that the mode used in Spain on this ceremony is better understood and more rational than elsewhere; the bodies are decently dressed, and carried on an open bier to the place of interment, into which it is placed, and with it a quantity of quick lime, which greatly facilitates the decomposition of animal substances, whereby the par|ticles composing it are the more readily enabled to form new combinations; they will quit the solitary abode of the dead, and will again be immediately brought into an active state of existence; their first combination will be to form vegetables, probably odorant plants and sweet scented flowers will owe their sweetness and beauty to the identical corpuscles that once animated our dearest friends and nearest relations, from whence through the medium of the atmosphere they will probably again con|stitute the rosy health and lively bloom of toasted beauty. In this rotine, for hundreds of ages, they have already in|vigorated our ancestors, and for thousands more to come will probably be performing the same duty for ourselves. How infinitely more joyous is such an exposition of facts than the hic jacet inrollment in vaults and church yards, and the solitary, gloomy and disgusting state in which the priests and ancient philosophers have supposed human bo|dies subject to. If notwithstanding these facts, preju|dice and vanity should still induce any to build sepul|chres for themselves and family, the legislature should order, that bodies consigned to such keeping should first be made a mummy of, in which state they may occupy a solitary nich in the gloomy dungeon, erected by big|gotry and folly, from whence on the commencement of a new state of things, they may in their mummied state, emerge to be held up to derision, as contraveners of the laws of nature. The atmospherical air is common stock, and ought not to be suffered to be polluted by any man's avarice or folly.

Would it not be infinitely better, both for the sake of humanity and commercial benefit, that when a malignant disease rages on board a vessel newly arrived in port, the

crew should be sent on shore to a proper situation, where necessary attendance could be given them, and the vessel, after being sufficiently impregnated with animal vital air, suffered to unload, than be obliged to perform that tedi|ous expensive and absurd operation called a quarantine?

This naturally brings us to the consideration of a sub|ject of some importance, to wit, Is the Yellow Fever contageous? By contagion I understand a specific dis|ease, capable of being communicated to a second person in one or two ways, either by actual contact and lesion of the skin, of which kind are hydrophobia, syphilis disease, leprosy, yaws and itch; or by the medium of the atmosphere through the absorbent vessels, on the surface of the body, of which kind are the small pox, measles, chicken pox, and hooping cough; these are all the dis|eases that are, literally speaking, contageous according to the definition of the word as above stated; but although I do not consider the Yellow Fever in all situations con|tagious, yet in certain cases it approximates so near to it, that it becomes difficult to draw the line. For in|stance, a man in health visiting a patient in the Yellow Fever, in an atmosphere that has not more than 20 per cent of animal vital air in it, would probably under cer|tain circumstances of heat and tendency, acquire the same disease; this looks something like contagion, though it be in fact very dissimilar, for let the patient be removed to a room where the atmosphere contains 28 per cent of animal vital air, and the heat and tendency are the same as in the former case, yet he might be visited there in per|fect safety. An hundred instances of this kind might, if necessary, be adduced from the history of the disease in Philadelphia and New-York. That vegetable vital air might be absorbed through the absorbent pores, or the sur|face of the body, I think extremely probable, but under what circumstances in might be done so as to become in|jurious to health, I can find no facts that lean to any cer|tain conclusion. Can animal vital air be absorbed in

the same way?(a) 1.10 it would become a very valuable discovery if it could be determined in the affirmative. It is a hint that might be improved on by those who have it in their power to make the requisite experiments. A means of determining with facility and certainly the exact pro|portion of the component parts of the atmosphere is likewise wanting; the utility of it is very obvious.

FINIS.

Notes

• (a) 1.1

  Mr. Lavoisier's experiments make the atmospheric air to be composed of 72 parts of azote, 27 parts of oxigen, and one of carbonic acid, or fixed air.
• (a) 1.2

  100 parts or pounds of nitre are composed of 30 pounds of ni|tric acid; 63 pounds of potash, and 7 pounds of water, which christalizes it.
• (b) 1.3

  The nitric acid is formed of 3 parts of vegetable vital air, and 7 parts of animal vital air, which was discovered by a very fine experiment made by Mr. Cavendish.
• (a) 1.4

  Mr. Chaptal observes, that respiration may be considered as an operation, by means of which, vital air posses continually from the gaseous to the concrete state; it must, therefore, at each in|stant, abandon the heat that held it in solution, and in the state of gas. This heat produced at every inspiration, must be pro|portioned to the volume of the lungs, to the activity of this or|gan, to the purity of the air, the 〈◊〉〈◊〉 of the inspirations, &c. &c.
• (a) 1.5

  Lib. VI. Obs. 9. Tom. 1, P. 25.
• (a) 1.6

  Fast. 17.Burn's Justice, Vol. II. P. 361.
• (a) 1.7

  Aleppo is in about the latitude of Baltimore. 6 Russel's Nat. Hist. of Aleppo. p. 192.
• (b) 1.8

  Van Sweiten Com. Vol. 16. p. 32.
• (c) 1.9

  Schrieber de pestilentia. p. 75.
• (a) 1.10

  Dr. Priestly, in making some experiments to ascertain to what source the colour of the blood is owing, relates a fact which al|most conclusively determines this question in the affirmative. He exposed fresh drawn blood to vegetable vital air, to atmospheri|cal air, and to animal vital air; in the first of which it quickly became black throughout, in the second, red on the surface but black below, in the third, the red on the surface was much more vivid: he then filled a bladder with blood and exposed it to animal vital air, which acquired a red colour over its whole surface. If then the affinity between blood and animal vital air is so great as in form an union through the intervention of a bladder, the probability is strongly to be presumed, that an union may take place on the surface of the body.