With regard to the state of the blood in this distemper, Dr. Rush says, that when drawn from a vein, it was, “1. In the greatest number of cases, dense, and of a scarlet colour, without any separation into crassamentum and serum. 2. In many cases it did separate into crassamentum and yellow serum. 3. In a few cases the serum was of a natural colour. 4. There were many cases in which the blood was as sizy as in pneumony and rheumatism. 5. In some instances the blood was covered with a blue pellicle of sizy lymph, while the part which lay in the bottom of the bowl was dissolved. In two cases the lymph was mixed with green streaks. 6. It was in a few instances of a dark colour, and as fluid as molasses. Both this and the 5th kind of blood occurred chiefly where bleeding had been omitted altogether, or used too sparingly, in the beginning of the disorder. 7. In some patients the blood in the course of the disease exhibited nearly all the appearances which have been mentioned. They were varied by the time in which the blood was drawn, and by the nature and force of the remedies which had been used in the disorder.”
From this account of the different appearances of the blood, it appears to have varied at the very first attack from an healthy state, and to have gradually deviated from that state more and more, as the disease advanced. Dr. Rush says,[150] from Dr. Mitchill’s History of the Yellow Fever in Virginia, in 1741, that “blood drawn from a vein was always dissolved. The same state of the blood was observed in many persons who had been exposed to the contagion, who discovered no other symptom of the disease.” In p. 70 Dr. Rush gives his own opinion in the following words: “I shall say, hereafter, that the blood was seldom dissolved in this fever;” and p. 73, speaking particularly of the blood, he enters into an argumentation against the putrescency of that fluid. “It” (the blood) says he, “has been supposed to undergo a change from a healthy to a putrid state; and many of the symptoms which have been described, particularly the hæmorrhages and eruptions on the skin, have been ascribed to this supposed putrefaction of the blood. It would be easy to multiply arguments to prove that no such thing as putrefaction can take place in the blood; and that the symptoms which have been supposed to prove its existence are all effects of a sudden, violent and rapid inflammatory action, or pressure upon the blood-vessels; and hence the external and internal hæmorrhages. The petechiæ on the surface of the skin depend on the same cause. They are nothing but effusions of serum or red blood, from a rupture or preternatural dilatation of the capillary vessels. The smell emitted from persons affected with this disease was far from being of a putrid nature; and, if this had been the case, it would not have proved the existence of putrefaction in the blood; for a putrid smell is often discharged from the lungs, and from the pores in sweat, which is wholly unconnected with a putrid, or perhaps any other morbid, state of the blood. There are plants which discharge an odour which conveys to the nose a sensation like that of putrefaction; and yet these plants exist at the same time in a state of most healthy vegetation: nor does the early putrid smell of a body which perishes with this fever prove a putrid change to have taken place in the blood before death. All animals which die suddenly, and without loss of blood, are disposed to a speedy putrefaction. This has long been remarked in animals that have been killed after a chace, or by lightning. The poisonous air called samiel, which is described by Chardin, produces, when it destroys life, instant putrefaction. The bodies of men who die of violent passions, or after strong convulsions, or even after great muscular exertion, putrefy in a few hours after death. The healthy state of the body depends upon a certain state of arrangement in the fluids. A derangement of these fluids is the natural consequence of the violent and rapid motions, or of the undue pressure upon the solids, which have been mentioned. It occurs in every case of death from indirect debility, whether it be induced by the excessive stimulus of contagion, by the volatile vitriolic acid which is supposed to constitute the destructive samiel wind,[151] or by violent commotions excited in the body by external or internal causes. The practice among fishermen in some countries of breaking the heads of their fish as soon as they are taken out of the water, in order to retard their putrefaction, proves the truth of the explanation I have given of its cause soon after death. The sudden extinction of life in the fish prevents those convulsive or violent motions which induce sudden disorganization in their bodies. It was remarkable that putrefaction took place most speedily after death from the yellow fever, where the commotions of the system were not relieved by evacuations. In those cases where purges and bleeding had been used it was much slower. There is a fact mentioned by Dr. Ferriar, from Dr. Hamilton, late professor of anatomy at Glasgow, which may seem at first to militate against the facts I have mentioned. He says that he had observed that bodies which were brought into the dissecting room that had petechiæ on them were longer in putrefying than any others. The fevers of which the poor (the common subjects of dissection) die, are generally of the low nervous kind. Great direct debility is the characteristic of those fevers. The petechiæ which occur in them appear in the last stage of this direct debility. They are the effect, not of too much impetus in the blood, as in the yellow fever, but of a defect or total absence of it in the last hours of life. The slow progress of the body to putrefaction after death, in the instances mentioned by Dr. Hamilton, seems to depend upon the same cause as that to which I have ascribed it in those cases of death from the yellow fever in which evacuations had been used, viz. direct debility. In the former cases this slowness of putrefaction is induced by nature, in the latter by art. The effects of debility from both causes are, notwithstanding, the same.”
From this long detail, in which the author’s meaning seems rather involved in obscurity, we may gather that in the fever of 1793 the blood had no determinate appearance, but that, according to the action of the vascular system, it was sizy or otherwise. This position, which in my opinion is the meaning of the passage just now quoted, is not supported by any facts. It is mentioned indeed that the blood in some was sizy, in others quite fluid, but as the cases in which it was so are not particularly related, we do not know whether the action of the vessels was stronger in those where the blood was fluid than where it was not. Certain it is, that the blood may be made fluid by certain substances mixed with it, without any action of the vessels at all. The poison of the ticunas, as well as all other animal poisons, renders the blood fluid, yet this will kill instantaneously when injected into a vein, before the vessels have time to act in such a manner as could be supposed to change the texture of any of the fluids.[152] Or if this still will not satisfy, we are assured that the poison of serpents, as well as many other substances, which are not poisons, when mixed with the blood taken out of the body, will prevent it from coagulating. Granting, therefore, what hath not been proved, that the greater the action of the vessels, the more fluid the blood will be, yet we cannot know whether this fluidity be occasioned by the action of the vessels, or the action of the vessels by the tendency to fluidity in the blood. But it matters not which of the two is cause or effect: the question is, Whether in the yellow fever does the ultimate effort of the disease tend to produce any alteration in the texture of the blood to fluidity, or otherwise? This can be known only from considering the symptoms which take place in the last stage of the disorder, and from dissections. Now, from the concurrent testimonies of all the writers quoted in this treatise, it appears that towards the end of the disease there is such a tendency to dissolution, that the whole body seems ready to fall down into a putrid mass; or at least into what is commonly called so, whether with strict propriety of language or not, signifies little. In short, the difference between the plague and yellow fever seems to be entirely of the same kind with that taken notice of in this treatise, p.p. [269], 270, where the bile of a person dying of a malignant fever was injected into the veins of a dog. Here the blood was very fluid. In capt. Mawhood’s case (p. [385]) the blood flowed from his nose, eyes and gums, besides what he discharged by vomit. Dr. Lining (p. [389]) attests a similar tendency to dissolution in the blood in a most remarkable manner. See also Dr. Lind’s opinion to the same purpose, p. [393], Dr. Hillary’s, p. [395], Dr. Jackson’s account, p. [399], Dr. Chisholm’s, p. [411]; and lastly, Dr. Rush’s own testimony concerning the hæmorrhages from all parts, lately quoted.
As we have formerly seen, that in the plague there was no such tendency to dissolution, but rather to coagulation, in the blood, it was thence concluded that the immediate cause of the symptoms of plague is a tendency in the blood to throw out the latent heat it contains, by which means the parts on which these discharges fall, are burnt up to a kind of cinder. In the yellow fever the reverse takes place. The blood has a tendency to absorb heat, and if it does so it must of course become thinner, for this is the nature of all fluids, and indeed it is abundantly manifest that fluidity in all cases is an effect of the absorption of heat.[153] In consequence of this absorption, the body towards the latter end feels cold, the heat seems to retire from the extremities towards the vital parts, and the vessels contracting and losing their power by reason of the abstraction of sensible heat, the pulse ceases entirely some time before death. Dr. Huxham takes notice of this excessive coldness in the limbs taking place in a lady who died of a malignant fever, and likewise that an intolerable stench issued from her body for some time before her death, though kept clean with all possible care. As the plague therefore is the highest of all inflammatory diseases, so the yellow fever seems to be the highest of the malignant class.
It may be objected, however, that as hæmorrhages, petechiæ, black vomiting, and convulsions, sometimes take place in the plague, we cannot from the existence of similar symptoms in the yellow fever, conclude that they are different diseases. But, with regard to the first, it must be observed, that an hæmorrhage may ensue from a rupture of vessels as well as from an oozing of blood in consequence of an acrimonious thinness of blood. It is indeed to be questioned, except in cases where blood is discharged by the pores of the skin, whether any hæmorrhage takes place but by a rupture of vessels. In an healthy subject, hæmorrhages very frequently take place from the nose where the blood is of a very proper consistence; and Dr. Russel says that he had occasion to see hæmorrhages from the nose and uterus only; that in the advanced stages of the disease though the blood was paler and of a thinner consistence, the hæmorrhage was seldom profuse. It was, however, of very bad omen; most of the cases in which it appeared having terminated fatally.
That towards the end of this disease the blood should begin to absorb the heat which it had before thrown out, is not wonderful. A tendency to dissolution very probably does in all cases take place in a greater or lesser degree; but we have not any reason to suppose that in the true plague hæmorrhages ever are as frequent, violent, or attended with such an apparent tendency to putrefaction, as in the yellow fever, and consequently we must suppose that there is some specific difference between the state of the blood in the one disease and in the other.
Convulsions, though very frequent in the yellow fever, yet, according to Dr. Russel, were very rare attendants on the access of the pestilential fever. Even hiccup was seldom observed, and sneezing not once. However, he says that convulsive motions of the limbs were frequently observed in the course of the disease; but this is far from what Dr. Chisholm says of the Boullam fever, where the patient expired in a violent convulsive fit; or what Dr. Rush says of the fever of 1793, in which the patient sometimes fell down in universal convulsions. In short, the absence, or much less frequency, of nervous symptoms in the plague, seems to constitute another specific difference between the two.
With regard to black vomiting, it is neither peculiar to the plague nor yellow fever. Dr. Miller[154] has shown that it may be occasioned by almost any kind of acrid poison taken into the stomach. In proof of this he quotes from Sauvages the case of a man who died in consequence of taking a drachm of white arsenic instead of cream of tartar, in whose stomach was found, on dissection, a black liquor which deposited a sediment like powdered charcoal. The villous coat of the stomach was likewise abraded. For other cases of the same kind he refers to Wepfer de cicuta aquatica, Morgagni, &c. Another case of poison by arsenic occurred in New-York hospital, in which the patient had a black vomiting. In another case in which corrosive mercury was swallowed by mistake, the patient, after being to appearance in a fair way of recovery, began to vomit a dark-coloured matter, and died in a day or two. The agaricus clypeatus, a kind of poisonous mushroom, brought on bilious stools, locked jaw, vomiting, delirium, oppression of the breast, sighing, anxiety, great prostration of strength, yellowness on some parts of the skin, and death on the sixth day. On dissection the stomach was found to be inflamed, the duodenum distended with flatus, and the gall-bladder full of green and black bile.
But the principal distinctions between the plague and yellow fever seem to be the eruptive nature of the former, and the propensity in the latter to attack strangers newly arrived from colder climates; also in being more easily checked by cold than the plague. It has already been remarked from Dr. Russel, that of two thousand seven hundred patients, whose cases he noted, every one had buboes. These, however, were not all the cases he saw; for he mentions some that had no eruptions; but from this it is impossible to avoid drawing the conclusion, that eruptions are the true characteristics of the plague. Of these two thousand seven hundred, eighteen hundred and forty-one had buboes in one or both groins; five hundred and sixty-nine had them in the arm-pit; two hundred and thirty-one had parotids; four hundred and ninety, carbuncles; and seventy-four, spurious buboes. Now, in all the number of cases of fever which Dr. Rush attended in 1793, he had only two with buboes, and one parotid; and as to the carbuncles they do not answer the description of those in the former part of this work.[155] It is impossible therefore that any more clear line of distinction can be drawn between the plague and yellow fever. The following table, however, exhibiting at one view the symptoms of the plague, the yellow fever, fever of Boullam, and fever of 1793, will perhaps set this matter in a still clearer light.
From a mere inspection of the detail of symptoms in this table, the difference between the several distempers is obvious. It is evident that none of them can with any kind of propriety be called higher and lower degrees of the rest. The plague is essentially different from the other three, which seem indeed to be nearly allied; the Boullam fever being only attended with more violent and malignant symptoms. We ought now to enter into a particular inquiry concerning the origin and nature of these fevers; but, as a knowledge of this is in some measure dependent on the question, whether or not they are contagious, we shall in the first place present the reader with the following extract from a French treatise, in which the question seems to be handled in an agreeable and judicious manner, and then make another attempt, by an investigation of matter of fact, to determine whether the disease has ever been excited by imported contagion or not: