“A pious and learned schoolmaster, who ventured to stay in the city during the plague, and took upon himself the humane office of visiting the sick and dying who had been deserted by better physicians, averred, that, being once called to a poor woman, who had buried her children of the plague, he found the room where she lay so little, that it could scarce hold the bed on which she was stretched. However, in this wretched abode, beside her, in an open coffin, her husband lay, who had some time before died of the distemper, and whom she soon followed. What shewed the peculiarmalignityof the air, thus suffering from human miasmata or effluvia, was, that the contagious steams had produced spots on the verywallof their wretched apartment. And Mr. Boyle’s own study, which was contiguous to a pest-house, was also spotted in the same frightful manner.” This shows not how infection may beproduced, but how it may be concentrated in such miserable apartments. The appearance on the walls brings to remembrance what is said in the book of Leviticus concerning the appearance of the leprosy in walls and clothes.
But, supposing we should allow that dirtiness may bring on a yellow fever (and it is plain that this cannot be proved) we have, in the case of the Busbridge Indiaman, ademonstrationthat cleanliness cannot keep it off.159This vessel sailed from England for the East Indies, in the year 1792, much about the same time that the Hankey sailed for the coast of Africa. She had on board 264 people in all, viz. 109 belonging to the ship’s company, 130 recruits, and 25 passengers. She hadvery boisterous weather at first setting out, but crossed the equator on the 26th of May, where the weather was sultry, with heavy showers of rain. The disease now made its appearance first among the recruits, and in a fortnight spread among the ship’s company. It was common for six or seven to be attacked with it daily from the commencement; “and in the space of twelve weeks almost every person in the ship not only had laboured under it, but many had suffered repeated relapses.” For several weeks the weather was hot and sultry; but, when in the vicinity of the Cape of Good Hope, they experienced a reverse, and were driven by a storm as high as S. lat. 42. Here the thermometer indicated a temperature only 13° above frost, but no material change in the disease took place. Afterwards, when returning into the warm latitudes, they experienced the sultry heats of the Atlantic without any change either for the better or the worse, and this for no less a space than three months.
As to the origin of the disease, Mr. Bryce the surgeon, though inclined to ascribe it to contagion, could not trace it to any origin of that kind, as the vessel had been six weeks at sea before it appeared. It “could not be ascribed to want of air or cleanliness, asevery possibleattention had been used to preserve these: the different apartments were thoroughly cleaned and fumigated with wetted gun-powder; the decks were sprinkled with boiling vinegar; and the windsails were attentively kept in order at each hatchway. Mr. Bryce is inclined to conjecture that a peculiar combination in the circumstances of diet, situation, and state of the atmosphere, may have given rise to this calamity. But the same combination of circumstances so frequently takes placewithout any fever, that it appears much more probable the disease had its origin either from animported fomes, or from afomes generated in some individual inthe ship, from whence it was afterwards propagated to others bycontagion.” The disease produced on board the ship was not contagious to the people on board another vessel with whom they hadcommunication, nor to the people ashore among whom the convalescents were put, nor to new passengers taken on board the vessel in the East Indies; circumstances certainly not a little surprising.
It doth not therefore appear, that, without the intervention of some other cause, mere dirtiness can produce the yellow fever. Let us next see what can be done by confinement, want of air, or, as it has been lately called, abstraction of oxygen. On this, however, we must observe, that in all cases where people are allowed to breathe, their lungs must be filled with the due quantity ofsomeelastic fluid. If the fluid they breathe contains a smaller quantity of oxygen, it must contain a greater quantity of something else. If a disease therefore is produced, it must be occasioned by thepresenceof that other fluid, as well as by the absence of oxygen. Now, in confined air, we know that not only the oxygen is diminished, and consequently a larger proportion of azote or septon mixed with it, but in addition to this increased proportion of azote, there is also a positive augmentation of the deleterious part of the atmosphere by the effluvia from the bodies of those who are confined. These effluvia, as we have seen, p.90, contain a great quantity of fixed air. Others have shown that they contain also azote; and it may be so; but still we are sure that the fixed air predominates. Besides this, from the breath we know that a great quantity of aqueous moisture proceeds. Experiments on the action of these different kinds of fluids are yet in an imperfect state, yet some important facts relating to them are known. 1. Oxygen breathed in great proportion produces an augmentation of heat, and proves an universal stimulant. See p. 118. By itself it quickens the pulse.1602. Pure fixed air breathed by itself destroys life with the circumstances of increased heat, rarefaction of the blood, and rupture of the vessels. See p.206. 3. The circumstances attending death by breathing azote are not particularly recorded;but we know that by breathing an atmosphere lowered by it the consumptive fever is not increased, but diminished; and there is an account in the Medical Annals of a person who was perfectly cured of a consumption by the smell of the bilge-water of a ship. 4. It has formerly been shown, from Dr. Black’s experiments, that, when the vapour of water is condensed in the body, a great quantity of heat must be thus communicated to it. In confined air therefore there is a diminution of the oxygen which produces heat; but there is an augmentation of the fixed air and of the aqueous moisture which increases it; so that, on the whole, the balance must be considered as in favour of the augmentation of heat in the human body; not to mention the quantity of sensible heat continually added to the atmosphere by that which evaporates from the body. This position, however, doth not stand upon the uncertain ground of theory; it is confirmed by the following remarkable fact: Commodore Billings, who commanded a Russian expedition fitted out by the late empress, found, in his travels through the northeastern part of Asia, that the cold of the atmosphere exceeded not only what was known in other climates, but even what most people had been able to produce by freezing mixtures. Dr. Guthrie informs us that he was unable to produce a greater degree of cold than 36 below 0 ofReaumur, though assisted by 20 below 0 of natural cold, and the power of all the freezing mixtures he knew. “How much then (says he) was I surprised to hear Mr. Billings assert, that some spirit thermometers which he had with him, graduated according toReaumur’sscale, were often as low as 40° below the freezing point of water, that is, 8 deg. below the freezing point of mercury. And once or twice he observed them at 42 deg. below thefreezing point of quicksilver.161
“During this severe cold (probably 42 below 0 of Fahrenheit) the Nomade Tchutski (a wandering nation on the northeastern extremity of the Asiatic continent) who were conducting him along the coast of the Frozen ocean, in sledges drawn by rein-deer, encamped every night on the frozen snow in low tents, which they quickly formed with the skins of rein-deer, spreading some of them on the surface of the snow, on which they all slept; and he assured me, that, so far from suffering from cold during the night, the heat was so excessive in these fur tents, where from ten to fifteen slept together, according to its dimensions, that no one could bear even a shirt; but all lay in a violent perspiration, naked as they were born, till dawn of day, without the aid of fire, excepting a train-oil lamp, which lighted each tent.”
From this account it seems pretty evident, that, by the accumulation of animal effluvia, a heat may be communicated to the atmosphere greater than that of the human body. We cannot suppose the heat of the tent which put the people in a violent perspiration to have been less than 90° of Fahrenheit; and, supposing the temperature of the external atmosphere to have been at a medium 30° below 0, there must have been a generation of 120 degrees of heat; but the heat of the human body does not exceed 97 degrees, and it cannot communicate more heat than it has. But we must suppose the tents to have been capable, had they been filled to the top, of containing twice the number who did sleep in them. They could communicate to the air thereforeonly one half of 97 degrees, or481/2°; the remaining711/2° therefore must been derived from the breath and perspiration of the body.162
Let us now attend to the consequences which must naturally and undeniably follow from this fact. If, in such a violently cold climate, the effluvia of fifteen human bodies could produce a heat sufficient to induce a violent perspiration, what would they not have done had they been in a climate where the heat of the atmosphere was upwards of an hundred degrees greater, or between 70 and 80 above 0 of Fahrenheit? Perhaps this was never thoroughly tried except in the black hole at Calcutta. Here an hundred and forty-six men and one woman were enclosed in a dungeon only 18 feet square, and consequently affording scarce eighteen inches square to each. This happened in a very hot climate, in the month of June; so that we cannot suppose the temperature to have been less than 80° of Fahrenheit.
On being confined in this manner, the vital powers endeavoured, by a most profuse perspiration, to send off the superfluous quantity of heat thrown into the body. This was exactly what took place with Dr. Guthrie; but, in the case of the black hole, there was, besides the quantity of heat produced by the warmth and perspiration of the body,an hundred and tendegrees more to be added, on account of the natural heat of the atmosphere. For we cannot suppose the heat at Calcutta, in a sultry evening in the month of June, to have been less than 80, which added to –30, supposed to be the temperature among the Tchutski, makes 110°. The perspiration was extremely profuse, and was soon accompanied with excessive thirst; nature being unable to supply such a quantity of liquid, or this liquid to carry off the heat from the body. The want of pure air began then to be felt by a difficulty of breathing; and Mr. Holwell, having in despair retired from the window, found the difficulty of breathing increase, attended by a palpitation of the heart. Aroused by his sufferings, he returned and was relievedby drinking some water, and having air at the window. The difficulty of breathing diminished, and the palpitation ceased; but, finding the thirst not to be quenched by water, he sucked his shirt-sleeves, which were wet with sweat, and endeavoured as much as possible to catch all of it that he could. The taste was soft and agreeable. A pungent steam was now felt like spirit of hartshorn. A number had died, and Mr. Holwell, once more rendered desperate, retired from the window, and lay down upon a bench, where he soon lost all sense. Next morning only 23 survived, of whom Mr. Holwell was one. He revived on being brought out to the fresh air, but was instantly seized with a putrid fever, as well as all the rest of the survivors. In this situation they were obliged to walk, loaded with fetters, to the Indian camp; at night they were exposed to a severe rain, and the day following to a sultry sun; yet, notwithstanding this ill treatment, they all recovered; having an eruption of large and painfulboilsall over the body. Mr. Holwell, however, said that he never afterwards enjoyed good health.
Another melancholy proof of the bad consequences resulting from a want of fresh air we have in the evidence given by Dr. Trotter, when the question concerning the slave trade was agitated before the British House of Commons. He deposed that the slaves were confined 16 hours out of 24, and permitted no exercise while on deck. They were kept in rooms from 5 to 6 feet high, imperfectly aired by gratings above, and small scuttles in the sides of the ship, which could be of no use at sea. The temperature of these rooms was often above 96 of Fahrenheit, and the Doctor says that he never could breathe in them, unless just under the hatch-way. “I have often (says he) observed the slaves drawing their breath with all the laborious and anxious efforts for life which are observed in expiring animals subjected by experiment to foul air, or in the exhausted receiver of an air-pump. I have often seen them, when the tarpaulings have been inadvertently thrown over the gratings, attempting to heave them up, cryingout, in their own language, ‘We are suffocated!’ Many I have seen dead, who, the night before, had shown no signs of indisposition; some also in a dying state, and, if not brought up quickly on the deck, irrecoverably lost. Hence, in one ship, before her arrival in the West Indies, out of 650 slaves, more than 50 had died, and about 300 were tainted with the sea scurvy.”
A third example of the effects of want of air, though conjoined with other causes, may be reckoned the case of the Hankey, formerly related. The people there were not indeed confined as much as in the black hole, but it is impossible to suppose that there could be a proper circulation of air, and the length of time the passengers were confined might be equivalent to the violence of the cause in the case of the black hole. In the latter, however, the disease produced was not the yellow fever, but seems to have been a kind of non-descript eruptive one, more resembling the small pox, or ratherJob’s disease, than any other. From Dr. Chisholm’s account of the Boullam fever also, it seems to have been more of an eruptive nature than the common yellow fever; so much, that Dr. Chisholm is of opinion that it partook “in no small degree of the nature of the true plague.” He says that in it he “did not observecarbuncleson any who died; but that in many who recovered they were numerous, large, and very troublesome.” He considered them also as a critical discharge, and the only one in this fever; but in the plague they certainly are not; neither is it at all probable that they were of the same nature with the pestilential carbuncles.
In p.207of this treatise it is inferred, from some experiments of Dr. Davidson and Dr. Chisholm, that the fevers in warm climatesare notowing to a deficiency of oxygen in the atmosphere; but in a treatise on the yellow fever in Dominica by Dr. Clarke, we have other experiments, which, if they can be depended upon, certainly overthrow that doctrine, or at least render it very dubious. Dr. Clarke endeavoured to ascertain the purity of the air by Mr. Scheele’s apparatus, and which waslikewise used by Dr. Davidson, viz. filling gallipots with flowers of sulphur and iron filings well mixed and moistened, and putting these upon a stand under a glass vessel, which was placed on a stool in a pail of water. The glass vessel was marked and divided on the outside, and, allowance being made for the space occupied by the gallipot, the water rose only one fifth in the glass vessel, after standing 24 hours. When the disease abated, it rose near one fourth; and upon many trials afterwards it never rose above one fourth. When the emigrants fled towards the mountains, where the air is very pure, they always avoided an attack of fever, or soon recovered if in a convalescent state. This is similar to what is stated by Van Swieten concerning the plague at Oczakow, viz. that the atmosphere was so loaded with some kind of vapour, that in certain parts of the town polished sword-blades were turned black. This seems to have indicated a great prevalence of inflammable or hepatic air, or both, in the atmosphere; but it is extremely doubtful whether this could produce afever, much less the trueplague. In Dr. Clarke’s experiments it were to be wished that he had examined the nature of that part of the atmosphere which was left after the absorption of the oxygen. It is by no means probable that at any rate the addition of a fifth part of azote could have rendered the air so unwholesome; and besides, we are entirely at a loss whence to derive such an immense quantity; for certainly the quantity of air which surrounds us, even for a few miles extent, is so great, that any considerable alteration in its composition could not take place without a very evident cause. The probability therefore is, that the experiments did not give an accurate statement of the quantity of oxygen contained in the atmosphere. Experiments on this subject must always be uncertain; and of all the modes of trying the qualities of the air, perhaps that with sulphur and iron filings is most liable to variation. It may vary, from the nature of the sulphur,163from the cleanness or the impurityof the iron filings, or lastly from the accuracy of the mixture. It is also a misfortune in this case, that though a great absorption proves the existence of a large quantity of oxygen in the atmosphere, yet a small one does not prove the contrary; for it is more reasonable to suppose that we have failed in our experiment, than that the constitution of the atmosphere has changed. Dr. Clarke’s experiments therefore cannot prove any thing, until more accurate methods of investigating these things be found out.
We must now proceed to investigate a third cause assigned for the production of fever, and that is the putrefaction of animal and vegetable substances. This hath been very much insisted on. Dr. Rush ascribes the fever of 1793 to the exhalations of putrid coffee, but allows also the distemper to have been contagious, and says, that “for several weeks there were two sources of infection, viz. exhalation and contagion. The exhalation infected at the distance of three or four hundred yards, while the contagion infected only across the streets. The more narrow the street, the more certainly the contagion infected. Few escaped it in alleys. After the 15th of September the atmosphere of every street was loaded with contagion; and there were few citizens in apparent good health, who did not exhibit one or more of the following marks of it in their bodies: 1. Yellowness in the eyes, and sallow colour on the skin. 2. Preternatural quickness in the pulse. 3. Frequent and copious discharges by the skin of yellow sweats. 4. A scanty discharge of high-coloured or turbid urine. 5. A deficiency of appetite, or a preternatural increase of it. 6. Costiveness. 7. Wakefulness. 8, Head-Ach. 9. A preternatural dilatationof the pupils. . . . Many country people who spent but a few hours in the streets in the day, in attending the markets, caught the disease, and sickened and died after they returned home; and many others, whom business compelled to spend a day or two in the city during the prevalence of the fever, but who escaped an attack of it, declared that they were indisposed during the whole time with languor or head-ach.”
Thus, according to our author, the fever of 1793beganfrom putrid effluvia, andwas continuedby contagion. But many attempts have been made to prove that putrid effluviaaloneboth begin and continue it. The limits of this treatise would not allow (even were it but beginning) of a particular account of all that has been said upon the subject; neither indeed is it needful. A single well attested instance would decide the matter; but we have already seen the difficulty of procuring that instance on either side. Certain it is, that we have instances of the yellow fever arising where it is not pretended that there was any considerable collection of putrid matters. In the Medical Repository, vol. ii, p. 149, we find an account of the yellow fever appearing “in a country village, near a fresh river,on low marshy ground, seven miles from Portland, so that no suspicion could arise of the disease being imported.Several other cases of yellow feveroccurredin different parts of the country.” This stands on the authority of Dr. Jeremiah Barker of Portland, so that there can be no doubt of its authenticity; and though it cannot prove that the yellow fevermay notarise from putrid effluvia, yet it certainly shows that itmayarise without them. It does the same with marsh effluvia; for though we may, in the case of the village, suppose that the marshy ground on which it stands occasioned the disease there, yet what shall we assign as the cause of its being dispersed in different parts of the country, where there were neither marshes nor rotten beef? The proofs indeed of animal effluvia being the cause of yellow fever are so equivocal, that Dr.Davidson164supposes putridvegetablematters tobe more active in this way than the former. For this supposition he gives as a reason, that Dr. Rush has observed, that butchers, and those who lived in the neighbourhood of shambles, scavengers, grave diggers, and others of similar employments, escaped the yellow fever in Philadelphia. These, the Doctor justly observes, were more exposed to what he calls thegazeous oxydof azote, than any other class; and he likewise takes notice, that sailors, who during long voyages feed on putrescent food, which might be supposed to produce a great quantity of this acid, are thence subject to scurvy, a disease not only different from fever, but entirely opposite to it. This exemption of people conversant among the dead has been also taken notice of by Dr. Mitchill,165who brings as an argument against the contagious nature of the disease, that “seven men belonging to the alms-house of New York were employed, during the whole of the sickly season of 1798, in putting the persons dead of the plague (yellow fever) into coffins, and though they handled in the course of their service upwards offive hundredcorpses, in different stages of putrefaction, and though they were much incommoded with the pestilential quality of the air in the rooms they entered, and frequently were obliged to vomit, not one of them was so much indisposed, during the whole season, as to discontinue his employment.” This is no doubt a very remarkable fact, but in the present instance it proves too much; for if, from it, we conclude that the disease is not contagious, we must also conclude that it cannot be produced by putrid animal substances. Yet in the very next sentence Dr. Mitchill assures Dr. Currie, “that exhalations from corruptingbeefandfishhave excited sickness as malignant, and as deadly, as any which has occurred.” If exhalations from putrefying beef and fish have produced this sickness, why did not exhalations from putrefyinghuman bodiesdo the same? and if we are assured that the latterdid not, we have as little reason to suppose that the formerdid; unless we establish a difference between the corrupting flesh of oneanimal and of another, which no experience hath countenanced in the least.
The exemption of those employed in burying the dead, even in the true plague, is observable. Dr. Canestrinus supposed it might be owing to the use of garlic, which they were wont to bruise and rub their hands, face and breast with, and likewise to chew, before they entered into an infected house; but this cannot be supposed a very powerful antidote. Dr. Rush is of opinion that grave diggers escaped in Philadelphia by the circumstance of their digging in the earth; and he says also that scarce an instance was heard of those employed in digging cellars being attacked with the disease. “There seems to be something (says he) in the fresh earth, which attracts, or destroys, by mixture, contagion of every kind. Clothes infected by the small pox are more certainly purified by being buried underground than in any other way. Even poisons, are rendered inert by the action of the earth upon them. Dogs have long ago established this fact, by scratching a hole in the ground and burying their limbs or noses in it, when bitten by poisonous snakes. The practice, I am told, has been imitated with success by the settlers upon new lands in several parts of the United States.”
This reason is very plausible for the exemption, of such as work in the ground, from contagion; but it cannot do for scavengers and butchers, who by the nature of their employment are frequently exposed to steams from the vilest matters. We may, on the contrary, derive from thence a very strong argument that these steams are by no means essentially connected with contagion. We have already seen from Dr. Fordyce (p.169of this treatise) that contagion or infection is not the object of sense. Dr. Rush, though he doth not absolutely say that the contagion of the yellow fever hath no smell, yet informs us, that “the smell of the contagion, as emitted from a patient in a clean room, was like that of the small pox,166but in most cases ofa less disagreeable nature. Putrid smells in sick rooms were the effects of a mixture of the contagion with some filthy matters. In small rooms, crowded in some instances with four or five sick people, there was an effluvium that produced giddiness, sickness at the stomach, a weakness of the limbs, faintness, and, in some cases, a diarrhœa. The contagion adhered toall kinds of clothing. It was in no instance communicated by paper.” From so great authority we may certainly conclude that,according to the best observation, there is anessential differencebetween the contagion of a disease and the effluvia of a putrefying carcase; and that, though the latter may be the vehicle of the former, and may increase its virulence, either by being partly assimilated to its nature, or by affording it a propernidusfor concentrating itself; yet that originally the one is not the other; and, though contagion may bring on a fever without putrid effluvia, yet putrid effluvia cannot do so without contagion. With regard to pure contagion, I shall here, to the evidences already produced, subjoin the testimony of Dr. Davidson, formerly quoted. “I mustdeclare167(says he) I have seen the disease evidently propagated in this way (by contagion;) but in many instances it could not be traced. I have known three cases of the fever brought on by persons bathing in the sea along side the vessel, some distance from the shore, and neglecting to dry themselves properly afterwards. The seminia of the disease were here present, and, like the electrical jar charged, required only the approach of a conductor.” This shows an amazing subtilty and diffusibility in the contagion, scarcely indeed credible, if it were not known to be equally subtile in other cases. In the correspondence between Dr. Haygarth, of Chester in England, and Dr. Waterhouse, professor of medicine at Cambridge near Boston, the latter informs us, from Dr. Rand, that by burning, in a field near Charlestown, the bedding, furniture, &c. belonging to a person who had been ill of the small pox, the people who lived in the wake of thesmoke proceeding from it were attacked with the small pox, and the disease spread. This is similar to an observation formerly quoted from Huxham; but the following are much more remarkable: “A vessel arrived at Charlestown from Lisbon, laden with salt, and lemons in boxes.168A person had the small pox on board, and the small pox officers would not suffer the lemons to be sold, without being first unpacked and the paper surrounding each lemon taken off. These papers were kept by themselves in a storehouse for several weeks; and after this, by order of the overseers, they were brought out and burnt; when, of two children playing round the fire, one, named Manning, took the disorder, and broke out at the usual time. . . .
“Dr. Rand was called to a lady, whom he found hot and feverish with a violent pain in her head and back; but he had no suspicion of the small pox. He bled her, and a Mrs. Brandon held the vessel to receive the blood, some of which spirted on her hand and arm. Next day the small pox appeared on the lady who was bled; and she was of course immediately separated from Mrs. Brandon; notwithstanding, in twelve or fourteen days, Mrs. Brandon was seized with the small pox, and died. Several other persons present were also liable to the infection, yet no one took the disease but this woman, who stood over the blood while it was running, and received some on her arm, except Mrs. Benjamins, to whom the bason of blood was handed over the bed, who also took the small pox from the effluvia of the blood. The same physician was called to the child of Manning (who was supposed to have taken the small pox from the burning of lemon-papers as aforesaid;) he found the child bleeding at the nose in its mother’s lap, who was then in the ninth month of her pregnancy. The next day the small pox appeared on the child, and it was of course immediately separated from its mother and all the family; nevertheless, in about fourteen days the mother was seized with the disorder, and not longafter delivered of a dead child, which childhad distinct eruptions over its whole body.”
These facts are of the utmost importance in determining the nature of contagious diseases. In conjunction with others, they show that such diseases originate in the blood, and from thence are communicated to the rest of the body. They show also, that the contagion is in all cases trulyspecific, andimmutable. Thus the contagion of the small pox, whether existing in the matter of a pustule, in the smoke of burning clothes or paper, or in the effluvia of blood, is invariably the same, and never produces any other disease. It is the same whether applied to the human body, or to that of a brute animal; of which we have a remarkable instance in the Medical Repository, vol. i, p. 258. “A peasant of the county of Essex, in England, seeing a great many children carried off by the natural small pox, was desirous of inoculating his two boys; one nine, and the other twelve years old. Not being able to employ a surgeon, he collected the scabs of a child then sick of the disease, powdered them, and sprinkled the powder upon slices of bread and butter. The two sons ate them, and gave a bit to the house-dog. They had a mild small pox, and got well without any remarkable accident. The dog remained sick for two or three days, drank a great deal, and refused to eat: on the fourth he had a very decided variolous eruption: on the ninth the pustules were full ripe, and dried up and fell off like those of the two children. An English author says he has seen the same epidemic in a flock of sheep, the greater part of which were infected, and communicated it to two cows, one of which died. The symptoms that manifested themselves in these animals in the course of the disease were in every respect the same as in the human species.”
This instance, partly quoted in the former part of this treatise, likewise is a strong proof of the contagion of small pox being first communicated to the blood; for, by swallowing it along with the aliment, it would, in the common course of digestion, be absorbed by the lacteals,and enter the blood with the chyle. The experiments with dogs made by M. Deidier, of which an account is given p.268, show that the contagion of the plague is equally specific with that of the small pox; and we see that it acted in all cases in which it was tried by being mixed with the blood. Being thus first mixed with the blood, it is plain that the contagion must have passed from this fluid to all the other parts of the body; and, if diseased blood is capable of communicating its disease to all the sound parts of the body in which it circulates, we must own that this strongly corroborates Dr. Waterhouse’s suspicion, “that the blood is capable of producing the infection before the disease is so far advanced as to be apparent on the surface.” If the disease originates in the blood, the latter should indeed seem more capable of communicating it at first than afterwards; because we must suppose that the diseased parts would be thrown off to the surface, and so pass off altogether. On this subject Dr. Waterhouse also quotes the opinion of Dr. Holyoke of Salem, “who, for his learning, professional abilities and integrity, is justly esteemed one of the first physicians in this country, and whose extensive practice has afforded him ample experience in the small pox.” He writes to Dr. Waterhouse, “that, although he has reason to believe that an infected person seldom gives the disease till after the eruption is considerably advanced, yet there are facts which make it probable that it is sometimes communicated earlier.”
In the same letter Dr. Waterhouse gives other instances of the inconceivable subtilty of variolous contagion, no less remarkable than those already mentioned. One is of Dr. Brattle, who, having visited patients infected with the small pox, “used the common precaution of covering his clothes with a loose gown, &c. but neglected hiswig. In consequence of this small neglect, after riding six miles on horseback, he gave the disease to a person in a room through which he passed, where he did not stay to sit down.” Another is, if possible, still more remarkable: “David Anthony, esq. one ofthe overseers of the small pox in Rhode Island, after going into the hospital, and using the common precautions, neglected tosmoke his wig. In his way home, two miles from the hospital, he called at the house of his daughter. He did not dismount, but sat on his horse, and talked to her through an open window; and, at the common period (by which we usually understand about fourteen days) she took the disease and died. Many such instances, adds the Doctor, could I relate, where wigs have given the infection, after being exposed to the open air during the passage of several miles.”
From all this it appears how difficult a task they undertake who contend for the domestic origin of the yellow fever, without contagion. In all cases they must have recourse to something visible and obvious to the senses. Thus putrid beef, putrid fish, ponds of water, marshes, &c. are all easily seen, and we are able to prove their absence as well as their presence. But we certainly know that the yellow fever has arisen where none of those supposed causes have existed, as in the Busbridge Indiaman; and, on the other hand, all the supposed causes have existed without the production of any fever. Of this last Dr. Chisholm, in the conclusion of his defence against Dr. Smith, gives the following remarkable instance:169“During a considerable part of the years 1776 and 1778 my duty led me very much to reside in New York; and during my residence, particularly in the summer and autumn of 1778, which were remarkably hot, and insufferably so in the lower streets of New York, no disease of a very alarming nature, and none which assumed the form of an epidemic, appeared among the troops or inhabitants. The smell from all the ships, and from those in particular delineated by Dr. Seaman (who has written a treatise on the subject) was in the highest degree offensive. The police at that time was by no means strict: putrid substances of every description were accumulated in the ships,and in many parts of the city unconnected with wharves, and yet no disease was the consequence.”
Some particulars above related may perhaps appear, to those who deny the existence of contagion, in rather a ludicrous point of view. It is indeed too common for people to laugh at what they cannot answer; but if we consider the instantaneous and inexplicable action of the poison of serpents, and in how little time they produce a mortal disorder, or even death itself; when we consider that contagion is only a volatile poison, and that it for the most part takes up an incomparably longer time to bring on death than the bites of some venomous animals; we cannot be surprised that a quantity of this volatile matter inconceivably less than that of animal poison should be capable of bringing on the disorder; for the length of time may be supposed to make up for the deficiency of quantity. Yet, if we consider the extreme activity of some animal poisons, the wonder at the small quantity of contagion necessary to produce a deleterious effect will in a great measure cease. In the former part of this treatise it has been observed, from Dr. Mead, that the whole quantity of poison emitted by a viper, when it bites, does not exceed the bulk of agood drop. An ordinary drop from a vial weighs half a grain, so that we cannot suppose a large drop to be more than a whole grain. But there are instances in which effects equally deleterious are occasioned by the bites of animals the whole bulk of which is scarcely equivalent to that of the poison of the viper. In the northern climates of the Old World,spidersdo not grow to any remarkable bulk, yet the bite of the poisonous spider of Russia is as mortal as that of the rattlesnake.170The effect of thefuria infernalisof Linnæus is still more to our purpose. It is an insect found in the forests of Kemi in Lapland, and likewise in Sweden and Russia; and, if we can give credit to Mr. Pennant, in some of the Western Islands of Scotland. This insect falls down out of the air, and, if it happens to light upon any uncovered part of the human body, it almost instantly penetrates downto the bone, occasioning the most excruciating pain, and death in aquarter of an hour.171Now, should we suppose the whole body of this insect to be poison, as it is probable that it is not, it is so minute, that though the whole were volatilized into contagion, it might be well supposed to adhere to awig, or even a more diminutive part of the clothing; and, considering the virulent effects of even this small quantity of contagion when concentrated, it would easily follow by fair calculation, that a veryminute proportionof even thissmall quantitymight bring on a dangerous disease.
Lastly, it may be urged on the side of contagion that, when a vessel arrives from a sickly country, it is no proof that she has not brought a disease with her, that the people aboard are in health. There is abundance of evidencethat very dangerous maladies may be communicated by those who do not labour under the same. The prisoners at the Oxford assizes were not sick at the time they communicated a dreadful distemper to those around them. Dr. Brattle and Mr. Anthony were in perfect health when they communicated the contagion of the small pox, yet the effect was not less fatal. In short,contagionbeing a power certainly known to exist, though invisible and imperceptible, it is impossible ever to prove that it is absent; neither after the contagion of any disease has once got into a country can we be assured that it may not revive. The experience, we may say, of the whole world testifies that it does adhere particularly to clothing. Dr. Lind thinks it may adhere to the timbersof ships; and there is the greatest reason to believe that it may also adhere to the walls of apartments in houses. The appearance of fever therefore without any new importation cannot prove that it has not arisen from contagion. But it is now time to state the evidence on the opposite side.
In Webster’s Collection we find the domestic origin of yellow fever supported by Drs. Valentine Seaman, and E. H. Smith of New York; and by Drs. Taylor and Hansford, and Dr. Ramsay of Norfolk. Dr. W. Buel of Sheffield has also given an account of a fever, but so unlike that of which we treat, that what is said of the one cannot be applicable to the other.
The arguments used by Dr. Seaman are, 1. Several persons were infected, who had taken the utmost care to avoid all communication with the sick, who had not been for several weeks out of their houses, or withineightyfeet of an infected person. 2. The nurses and attendants in some places were infected, but in others generally escaped. Neither did the disease spread into the country, as was reported; the Doctor having inquired into these reports, and found them groundless. 3. Dr. Lining says in his letter to Dr. Whytt,172“If any person from the country received it in town, and sickened on his return home, the infection spread no further, not even to one in the same house.”173
Several other arguments of the same negative kind are adduced, which, being not essentially different from those already quoted, it is needless to detail. The following are rather of a different nature: 4. Some contagions are propagated by contact only, others at a distance; but at any rate we may suppose that contact will propagate contagion more readily and more powerfully than any other mode that can be imagined. Yet multitudes of dissections have been made, and those who made them are still alive. 5. “Specific and acknowledged contagions all seem to arise from themselves only: henceit would be almost as hard for me to believe that the siphylis, small pox, or measles, could be produced from any other cause than their own proper virus, obtained from persons affected with the like disease, as it would be for me to conceive of the formation of a plant without its having received its seed, orradical, from one of the same nature.174Contagions seem to fix in the soil of our bodies, and there seed, as naturally and regularly as vegetables do on the earth. But the yellow fever has been produced fromother causes than contagion.175Does it not then admit of a doubt, whether itcan possessa power of propagating itself?” 7. Contagions respect no persons, but all of every clime and colour are equally attacked with them; but the yellow fever is known to attack some much more readily than others. 8. Contagious diseases generally have a determined time of invasion after an exposure to their cause: but the advocates for contagion in the yellow fever cannot be confined in this manner. “Their doctrine requires that it (the contagion of yellow fever) be permitted to act at any time between that of the exposure and the sixteenth day; otherwise it would not embrace cases enough to give it a currency.”1769. “Contagionsact more or less at all places and seasons, simply of themselves, without the aid of any particular circumstance of air or climate; but the supporters of the yellow fever being contagious are obliged,by the force of the foregoing observations, to acknowledge theirimaginary fondlingto be but ahalf-formed monster, and perfectly inactive without being assisted by the concurrence of a predisposing constitution of the air. (Rush on yellow fever.) This fever exists only in warm weather: hence its cause in this city (New York) was perfectly extinguished by the frosty nights in the 10th month. It is confined mostly to low situations in thick-settled places; otherwise our almshouse and the surrounding country would have sadly experienced its deleterious effects.”
This argument merits a particular consideration, as involving a question of very great importance, namely, concerning the constitution of the atmosphere, which we have had occasion formerly to speak of, and which is by some thought to be sufficient of itself to produce epidemics, without the intervention of any other cause. This constitution of the atmosphere is, it is true, somethingunknown; and, when people appeal to it, it is only in other words owning their ignorance; but the necessity of recurring to some cause imperceptible by our senses has in all ages been obvious. So much indeed has been said in this treatise on the causes of plague (which may apply also to yellow fever)177that more would be superfluous, even if our limits would admit of it. The dilemma (and it is equally insoluble let us say what we will) stands thus: If the yellow fever is produced by the effluvia of marshes, by putrid streams, or by any thing else, how comes it to pass that it has been so frequent in the United States since the year 1792 in comparison of what it was for 30 years before? Have the American cities all at once become sinks of filth and nastiness? Have the seasons been changed, or have the inhabitants given themselves up at once to swinish intemperance andgluttony, devouring, like savages, their meat half-rotten, half-roasted or half-boiled? From some declamatory publications indeed one might be apt to think that the authors certainly meant to bring such accusations against them. But it undoubtedly will be found an hard matter to prove that the general cleanliness of the country is inferior to what it was, or that the people are less virtuous than they were before. Besides, has not the vigilance of the magistrate, ever since 1793, been exerted to the utmost to procure a removal of those nuisances from which the disease might be supposed to arise? Yet their efforts have not availed; for it is confessed that the attack in 1798 was the most severe ever experienced. If cold could have exterminated the disease, certainly the three last winters have been abundantly sufficient to do so; yet it is certain that cases of the fever did appear in the end of December last, when the cold must certainly have been deemed sufficiently intense to put a stop to putrefaction of every kind. No wonder then that people, unable to see the causes of these things, should have recourse to something invisible, which they called theconstitution of the atmosphere. On this subject Dr. Haygarth of Chester makes the following objections to the commonly received opinions concerning epidemic constitutions of the atmosphere:178
“1. Dr. Odier of Geneva, in a letter to Dr. Haygarth, writes thus: ‘I believe it would not be difficult to prove that the state of the atmosphere is in no respect the cause (of the regular epidemics of that city;) for the villages and towns which surround it do not experience the same epidemic all years as Geneva, although they are situated under the same heavens, and exposed to the same vicissitudes of atmosphere.’ 2. Sydenham conjectures that some effluvia, issuing from the bowels of the earth, produce epidemics. Were this true, it might advance one step towards a solution of the difficulty by discovering a local difference in the atmosphere. But it has never yet been pretended that any such vapour was perceived. Yet every part ofthe earth must be capable of furnishing it; as no portion of the whole habitable globe has been discovered where the air could not propagate the small pox. . . . 3. Hence we may safely conclude, that the slight variations of the same climate, and the same season, must be altogether insignificant and nugatory. What important difference of atmosphere can be supposed to exist for weeks or months together in two neighbouring villages, or in the adjacent streets of the same town? This remark is plainly applicable to the propagation of the plague and other infectious distempers. Yet the latest and most respectable authors continue to be misled by this groundless hypothesis.”
Objections of this kind do not solve the difficulty. The excessive disparity of seasons with respect to the spreading of epidemic diseases, the long cessation of them at some times, and their sudden revival, as if with redoubled fury, at others, indicate the operation of some cause invisible to us; but whether that cause resides in the earth or in the air, cannot easily be known. As contagious matter seems to operate by being received with the air into the lungs, it would seem rather probable that the ultimate cause of epidemics resides also in the air. Dr. Haygarth complains that thevapourarising from the earth, supposed to produce epidemics, should be invisible; but the contagion of the small pox, or of any other infectious disorder, is equally so. It must, he says, be diffused all over the earth. The electric fluid is so; it issues from the earth in every part of its surface, as is demonstrated by the common experiments of electric machines; and there are the strongest reasons to believe that it issues at some times and in some places in much greater abundance than others. But enough has been said on this subject; we must now consider matters a little more obvious.
Though it is not easily seen in what manner the proportion of the ingredients which compose the atmosphere can be changed, and we are unable to discover the operation of the more subtile fluid contained in it, yet we are certain that its constitution must be different in differentparts of the world. Islands, from their being surrounded on all sides by the sea, must of consequence have an atmosphere considerably different from that of the internal parts of continents, where the air always passes over large tracts of land. Hence the continent of America, being situated between the two vast oceans called theAtlanticandPacific, must possess a constitution of atmosphere considerably different from that of the Eastern. Of consequence, the diseases of Europe and Asia, when transplanted to America, or to the American islands, will probably, sooner or later, assume a type different from that which they had in their own country. Dr. Waterhouse has taken notice of this in his letter to Dr. Haygarth, and thinks that it may hold good even in the small pox. “May not the small pox (says he) operate differently in the two countries? It has certainly had a different appearance, and required a somewhat different treatment, almost every time it has come among us. That the difference in the virulency of the small pox, observed at different periods, when epidemic here, may be attributed to a peculiar constitution of the atmosphere, no one seems to doubt; and why may not the difference, so reasonably to be expected between the atmosphere of your island and this continent, allow us to suppose that there is some difference in the facility of receiving the infection?” This is also an important consideration, and may throw some light on the cause, as well as the mode of prevention, of this disease.
Lastly, Dr. Seaman attempts to disprove the authenticity of some cases which have been brought as positive proofs of the disease having been received by infection. These belong not to us to consider; it being impossible, by reason of the invisible nature of contagion, to determine from a simple consideration of any patient’s case whether it was infectious or not. Dr. Fordyce has laid down the proper rule for judging in such cases.179One only of the instances brought by Dr. Seaman therefore we shall mention, and that, not because it proves anything, but on account of its singularity. “Daniel Phœnix, city-treasurer of New York, is supposed without doubt to have taken his complaints from contagion: the corporation, some time past, having issued into circulation, for the accommodation of the inhabitants, a great number of paper penny bills, it has been concluded that he must have received contagion through the medium of some bundles of these bills, which he opened, that had been nearly worn out, to be exchanged, and which he opened and examined to ascertain their amount some days after he had received them.” The Doctor allows that he might have been infected by the bills, but ascribes it to putrid effluvia.180
Dr. Smith, in his letters to Dr. Buel, insists much on the vitiated state of the atmosphere, and is at some pains to describe the persons who were most subject to it. These, in 1795, were for the most partforeigners; under which denomination the Doctor comprehends those who came from other states, from the West Indies, and from Europe, or who had not been many months or years settled in the city. The number of citizens who suffered he does not suppose to have exceeded one in seven; but he remarks, that, both among foreigners and citizens, the severity of the disease fell chiefly on the poor. This mixture of different nations he accounts, and with great probability, one of the causes of the distemper.In confirmation of it he quotes Dr. Blane, on the diseases of seamen, remarking, “that it sometimes happens that a ship, with a long-established crew, shall be veryhealthy; yet if strangers are introduced among them, who are alsohealthy, sickness will be mutually produced.” The same observation is made by Dr. Rush, who, besides a general reference to the history of diseases, adds the following remarkable fact: “While the American army at Cambridge, in the year 1775, consisted only of New England-men, whose habits and manners were the same, there was scarcely any sickness among them. It was not till the troops of the eastern, southern and middle states met at New York and Ticonderoga, in the year 1776, that the typhus became universal, and spread with such peculiar mortality in the armies of the United States.”
This confirms the observation made in the former part of this treatise, when speaking of the English embassy to China. It may likewise with probability be assigned as one reason why large manufactories are generally so unhealthy. In them there always is a collection of people from many different and distant parts; and what holds good on a large scale must also do so on a smaller one. But this does not disprove the doctrine of contagion, but rather confirms it; for, if the discordant effluvia rising from healthy bodies of differentconstitutionscangeneratea disease, much more may we suppose the effluvia from sick persons capable of continuing and propagating it.
Now, let us consider the account, imperfect as it is, which we have been able to collect concerning the appearance of the yellow fever on the Western Continent. We have seen (p.377, n.) that, at the time the plague was in England, five of the Americans were transported to that country; two of whom, after staying some time in England, were sent back, with other strangers, to America. This first colony having failed, another was sent; the Indians went to war among themselves, and the yellow fever is supposed to have made its appearance. Here a suspicion naturally arises, that a slightpestilential taint had been imported by some of these strangers, and that what would have been thetrue plaguein Europe or Asia, by reason of the peculiar constitution of the atmosphere in the New World, there became theyellow fever. The same may be said of the original importation of it into Martinico. Sauvages expressly says it was theplaguewhich was imported. Moseley and others deny that any such disease as the yellow fever exists in Siam; and indeed it seems at any rate to be a new disease. It seemspossiblethat diseases may change their nature; and Dr. Ferriar has given a dissertation on the conversion of diseases. As therefore the true plague never made its appearance in America or the West Indies, it seems not unreasonable to suppose that these countries are incapable of receiving it, but that the pestilential poison, when transported to the Western Continent, may assume a different, and in many respects an opposite, nature; the two diseases being thus like the opposite poles of a magnet, scarce agreeing in any thing but the common work of destruction.
It is needless to spend time in attempting to investigate the cause of this disease appearing at different periods. That of 1793 has been the most remarkable and the most destructive; the disease having never since that time ceased its ravages. Previous to its appearance at Philadelphia that year, Dr. Rush observes, that, “during the latter part of July, and the beginning of August, a number of the distressed inhabitants of St. Domingo, who had escaped the destruction of fire and sword, arrived in the city. Soon after their arrival the influenza made its appearance, and spread rapidly among the citizens.” The yellow fever quickly followed; for on the 5th of August the Doctor mentions his being called to his first patient. To the same purpose we are informed by Dr. Clarke that “the fever made its appearance in Dominica about the 15th of June, 1793, a few days after the arrival of a great number of French emigrants. They were not sick, and the fever had not made its appearance in Martinique when they left it. From the 1st of July to the 1st of October itwas computed that eight hundred emigrants, including their servants and slaves, were cut off by this fever; and about two hundred English, including new comers, sailors, soldiers and negroes, all fell victims to it in the same space of time. Few new comers escaped an attack, and few recovered. It spared neither age nor sex among the Europeans and emigrants; and not only the people of colour from the other islands, but the new negroes who had been lately imported, were all attacked. Such as had been long on the island escaped.”181
These facts seem to point out one of the causes, and very probably a principal cause, of this dreadful distemper. They show very evidently that there is a connexion between war and diseases. It has formerly been attempted to point out a natural connexion between the horrid practices of men, on these occasions, and the production of disease. These investigations, however chimerical they may be reckoned, are yet supported by many facts, which undoubtedly prove that mankind cannot always maltreat and torment one another with impunity. The affair of the Black assizes, and Old Bailey session, in 1750, shows, that by confinement and bad usage the human body, without being apparently deprived even of health, may become poisonous to those around it, and produce dreadful diseases. In like manner the inhabitants of St. Domingo, having been put to the most dreadful distress, became properly fitted for spreading destruction wherever they went.182It is even probable that, in proportion to the degree of distress suffered by these people, the disease communicated by them will be malignant; nay, that new diseases may spring up, which cannot be treated with success by anymethod yet known to physicians. With regard to the disease in question, it seems plainly to have from some cause or other received an additional malignity. Dr. Chisholm says that what he calls the Boullam fever was supposed in Grenada to have been the common yellow fever of the West Indies engrafted on the jail fever. Dr. Lind, Dr. Jackson, and even Dr. Chisholm himself, agree that the former is not infectious: but from what has been already said the evidence seems to prevail in favour of the opinion that the latter is so. Should we then allow that two kinds of this fever might exist at the same time, in one city, the difficulty would be at once removed. But this has been reckoned by many, particularly by Dr. Rush, as totally inadmissible; and indeed it is a maxim consonant to general experience, that two epidemics cannot exist in one place at the same time, or that two diseases can scarcely exist at once in the human body. This however must be understood, principally at least, of acute diseases, or such as affect the whole system; for if any disease of a particular part shall take place, it does not seem impossible that a fever may be superadded to such local disease. The following considerations may perhaps throw some light on the subject:
It appears from the experiments of Dr. Adair Crawford, that, when animals are immersed in hot water, the blood drawn from a vein is of a florid red colour. In summer it is likewise observed to be of a more florid colour than in winter. If heat thus gives a more bright red to the blood, it undoubtedly also makes it more fluid, and in proportion to its fluidity it will likewise become acrimonious; though this acrimony is not necessarily connected with a florid colour, as the blood of the arteries is not more so than that in the veins. In the yellow fever, however, the blood sometimes, towards the end of the disease, becomes endowed with extreme acrimony. Dr. Smith, in one of his letters to Dr. Buel, observes, that “blood drawn in the fever of 1795 was remarkablywantingin floridity; especially what was evacuated towards the close of the disease, whether by art, or spontaneous effusion. In one instance it seemedendowed with a caustic quality, and affected a lancet so as to leave a permanent discolouration and inequality on its surface.” He observes also, nay, considers it asdemonstrated, that the yellow feveris nota disease of vascular debility, and he says that it is attended with an astonishingfluidity, or, as it is called,dissolutionof the blood. Every one therefore who comes from a cold to a warm climate must in some degree or other have his blood liquefied, and in a certain proportion rendered more acrimonious than before. This acrimony may be undoubtedly augmented by certain causes, and by none more probably than immoderate drinking of spiritous liquors. Every one therefore who comes from a cold country to a warm one, especially where the air is also moist, may consider himself as already diseased, at least in comparison with what he was when at home. For the blood is now exposed to a greater degree of heat, and consequently is about to absorb, or rather may be considered as in the act of absorbing, more, and consequently of changing from a thicker to a thinner or more fluid state; the latter being the natural situation of the blood in warm countries. Dr. Rush, in his inquiry into the proximate cause of fever, has accounted for the dissolved appearance of the blood in malignant fevers to a tendency in the blood-vessels to paralytic affection. He says that “it (the dissolution of the blood) begins in the veins, in which muscular action is more feeble than in the arteries. This has been proved by Dr. Mitchill in his account of the yellow fever in Virginia in 1741. He found the blood to be dissolved when drawn from the veins, which, when drawn from the arteries of the same persons, exhibited no marks of dissolution.” This, as the Doctor observes, “is a fact of great importance;” only we must remember, that, in every thing relative to the human body, when we find two phenomena constantly accompanying each other, it is extremely difficult for us to determine which is cause or effect. Instances of this often occur; and in the present case the dilemma is as great as any other. Though, from the testimony of Dr. Mitchill, we cannot doubtthat in yellow fever the dissolution begins in the veins; and though it is likewise extremely probable that this dissolution is attended with a paralytic tendency, we cannot know whether the dissolution is the cause of the paralytic tendency, or the paralytic tendency the cause of the dissolution. The point, however, is of no importance. We see that in warm climates the blood of a person newly arrived has a natural tendency to dissolution, and of course the veins to the paralytic affection just mentioned. The liver therefore, which is supplied with blood by a large vein branched out like an artery, and terminating in other veins to carry back the blood from the former,183must be much more affected than any other part of the body; and this indeed seems a very probable reason why all those who come to warm countries become much more inclined to bilious complaints, which denote an affection of the liver, than they were before. This hepatic affection may very probably be greatly augmented, in new comers, by various causes. One of these is hard labour under a greater heat than they have been accustomed to; a second, that in the West India islands they have not access to that plentiful supply of fermented liquor, abounding in fixed air, which they had at home. This, though not generally taken notice of, is far from being a matter of little consequence; for, though emigrants from Britain and Ireland have been for the most part accustomed to drink spiritous liquors, yet fermented malt liquors certainly constitute the principal part of their drink. The total want of these, and the substitution of ardent spirit and water, must certainly be detrimental, even though they keep within the bounds of moderation, and much more if they do not. Dr. Moseley relates,184from Dr. Irving, that, in a bad kind of intermittent which broke out among the troops in service on the Spanish main in 1780, “nothing was so grateful asLondon bottled porter. Wine was neither so much desired by the sick, nor so serviceable in corroborating and keeping up the powers of the stomach; which, likethe rest of the body, was soon reduced, from the slightest indisposition, to the lowest state of debility.” A third cause is no doubt their frequently drinking too freely of spiritous liquors, perhaps not of the best quality; and which, as they are neither conjoined with the fixed air nor with the mucilage which as it were inviscate and blunt their force in malt liquors, cannot fail of exerting their deleterious properties in a very remarkable manner.
From these and other causes there must necessarily arise a predisposition to hepatic diseases; and this predisposition cannot be removed until the blood has assumed the state of fluidity proper to the climate in which they are, and the body has acquiesced in the change. They are then said to beseasonedto the climate; and it is seldom that this seasoning takes place without a disease; indeed so seldom, that the first illness which happens to seize them after their arrival is called theseasoning. Dr. Trotter indeed gives a very different account of this seasoning. He considers those who come from a cold to a warm climate as having a redundancy both of excitement and excitability, and says that “towear out this accumulated excitabilityby slow and gentle gradations is the grand explanation of the wordseasoning: it is thesecretwhich constitutes the only difference between the inhabitants of England and Jamaica. The yellow fever of the West Indies therefore, as it appears in the body of a raw European, is a disease of theutmost excitement, in a constitution ofaccumulated excitability; where a tense fibre and dense blood permit it to be carried to the highest pitch of inflammatory tendency; which, from the nature of the animal economy, speedily exhausts the powers of life, even in a day or two, inducing putrefaction and death.”
Explanations of this kind may edify those who understand them; but, though we should declaim ever so much about excitement and excitability, it is plain, that, in every one who comes from a cold country to a warm one, the liver is affected in a manner that the rest of the body is not. In some constitutions, or from excitingcauses in any constitution, this affection of the liver may be augmented, and no doubt at last produce a bilious fever, which may be varied in a number of ways, according to the nature or the energy of these causes. The pure bilious fever, being of itself properly a local affection, may not be contagious; and we find it generally agreed among physicians that the common yellow fever of the West Indies is not infectious. Nevertheless, it seems by no means improbable that from certain circumstances contagion may be joined with it, and it may then spread and infect, even as the most deadly plague. Dr. Crawford relates, that, in the year 1770, a new kind of fever broke out in the Middlesex Indiaman, of which many died. It is not said that the disease was contagious; but, on opening the bodies of some who died, the liver was found enlarged, and of a more florid colour than it ought to be. It cannot be deemed impossible that contagion, even that of the true plague, might be mixed with this fever, which (as the affection of the liver was probably the original disease, might have been accounted little other than symptomatic) would then have assumed very malignant symptoms.
We might now say that we have got to the end of our subject. Having so amply discussed the question concerning contagion, and stated the principal part of the evidence against it, it seems proper to conclude the section with a short history of the disease in the malignant form it has assumed in the United States since the year 1792. Still, however, it is necessary to say something further of one or two of the causes which have been commonly assigned as necessarily inducing this disease. These are, 1. Extreme heat, and, 2. Marsh effluvia. The effect of the former has already been partly considered as a predisponent cause of yellow fever: but it doth not appear that merely from this cause the disease has ever been produced. It hath indeed been observed by very intelligent physicians, that in Virginia the remitting fever has often been brought on by mere exposure to the sun. Dr. Oliver of Salem hath obliginglyinformed me, that he has “in more than one instance been seized with that disease after riding in the sun;” and that an eminent practitioner in Virginia had informed him that he had also more than once suffered in the same way. Drs. Taylor and Hansforth observe, that, when the remitting fever proves mortal, it is generally attended by sickness and perpetual vomiting; which is the termination of the yellow fever. The above evidence is decisive with regard to heat being able to produce a remittent, but cannot exactly apply to the yellow fever, which has no remissions. Two sailors indeed, lately brought from a coasting vessel to the Salem hospital, were attacked with violent symptoms of yellow fever without having been, as is said, exposed to any infection. But evidence of this kind cannot be supposed to be incontrovertible. We have already seen the difficulty of ascertainingfacts; and if it is difficult to prove that contagionhasbeen received, it must be still more so to prove that ithas not. The persons in question had both worked during a very hot day in a vessel’s hold, they afterwards sat exposed in the damp air of the evening on the deck until 10 o’clock at night, and then slept in the vessel’s cabin with the windows open. One of them was seized in the night with a most violent pain, and the other on the morning succeeding. It is said that about 11 months since this vessel was at New York, and that a person on board had the yellow fever; it is also alleged that the vessel was not purified, and that the beds remained on board. It has therefore been by some conjectured that the disease might have been derived from this source.
Dr. Ramsay, in a letter to Dr. Currie of Philadelphia, censures Dr. Lining for saying that the yellow fever was imported into South Carolina. “The greater yellowness of the skin (says he) appears to be the only circumstance in which it differs from the bilious remittent fevers of hot climates, or very hot seasons of any climate.” Our author also censures Dr. Lind of Haslar,185who, hesays, has been misled by themisrepresentationsof Dr. Warren and others. He also gives into the opinion that contagion acts only by contact, or at a very little distance; but this subject we cannot enter farther into at present. If we can believe Dr. Moseley, the sure criterion by which the yellow fever may be distinguished from any other is, that the former hath no remissions.186If solitary cases of it appear in Carolina and the southern States every year, this will not prove that the disease was generated in the country, any more than that the plague was generated in London, because it appeared there for many years successively.