or more, when let at, or nigh the ftate of the disease; and about one half at the beginning: after the state or height, it feems by the pulfe to be more: a large proportion for an acute continual fever; even those who are bled after a received contagion before the fever is formed, have a thin diffolved florid blood, even in winter. This was the conftant state of the blood in about thirty or forty whom I have known to have been bled, at all feasons of the year. But the arterial blood which I have had an opportunity of seeing was very different. Feb. 17, 1741-2, five or fix ounces of blood were taken from the temporal artery of one labouring under this disease, on the fourth day, just as the yellownefs began to appear in the eyes, attended with a ftupor; this blood was not more florid than what the venous blood generally is in this distemper: when cold it had a purulent yellow skin or inflammatory cruft on the top, exactly resembling the cruft on the venous blood of pleuritics, but not very thick, although tough and not eafily divided; the craffamentum was very cohesive, thick and blackish at bottom; the ferum made not above a fixth or eighth part of the whole, which was of a deep yellow or faffron-colour, and would tinge the finger or a linen rag dipped into it, of the fame colour as if dipped in gall; deeper than is commonly to be feen on a rag dipped in the urine of perfons in a jaundice. On this every one that faw this blood was convinced that the diftemper was what is generally called the yellow fever in America.

"Dr. Langrish fays, we are not yet well informed of the state of the blood in malignant fevers; this perhaps may be fome help to a more certain and general determination of that neceffary point.

"It is of the greatest importance in the cure, to know the course and stages of this disease, and the different changes it undergoes from first to laft; with the times when they may be expected. By an account of this we may fatisfy an ingenious query of the learned Dr. Cliffton in his Hippocrates, p. 260, to wit, Whether the obfervations concerning the course and periods of acute difeafes, delivered by Hippocrates, hold true in

places at a greater diftance, fuch as the Eaft and West Indies, America, &c.? This is reckoned a difeafe as peculiar to our new world as any other, and confequently as fit to adjust this matter by; which, if once determined, may make those excellent obfervations as univerfal and extenfive as they are useful. But I have not only obferved this; but likewife other epidemic difeafes, which owe their rife to a certain uniform caufe, which feem to be the difeafes chiefly pointed at by Hippocrates in his Prognostics, to have the fame courfe and periods in Virginia as delivered by the father of phyfic.

"This fever was exafperated on equal or unequal days, tilk the fourth, which was what is called the state of the disease here in Virginia, in the winter and fpring feafon, when the disease has chiefly raged here: on this day the figns of the yellow effufion began to appear, either in the eyes, or by vomiting and purging; this day was the index of the feventh. All good changes or favourable symptoms now denoted recovery on the feventh, as any bad appearances on this day portended death on the fixth. If the exacerbations were on equal days, they generally died in the third paroxyfm, or the fixth day; but if on ́unequal days, they recovered on the feventh. Relapses happen either on the eleventh or fourteenth, which were adjudged on the fourteenth or feventeenth refpectively; and this without exception in any, except thofe in whom the natural course and tendency of the distemper was prevented by a preposterous method of cure, or fudden and extreme severity of the disease, and all the regular efforts of nature overfet thereby.

"This distemper is remarkably contagious, of which we had the better opportunity to be satisfied here in Virginia, where we live in feparate and distant plantations, confifting of numbers of fervants and flaves; any of whom, if the diftemper once feized, there was little fecurity for the reft, but removal. The diftemper spread rather flower than I have obferved the measles or fmall-pox to do here; but it fpreads faster and rages more violently in the fpring feafon, or from Christmas to Whitfuntide, than any other time of the year; which I have likewife

obferved of these other diftempers in Virginia. But the viciffitudes of our seasons in Virginia, where the changes in the feafons are reckoned greater than in any other place whatever, or our care in prefer ving against it, feem to have put a stop to the contagion. But it is likely that in the West Indies where they have no fuch viciffitudes of feafons, which are generally obferved to put a stop to a peftilential contagion in northern climes, they may hardly ever get rid of this diftemper, (no more than the Turks in Afia and eaftern nations do of the plague,) without a purification of the infected places, or feparation of the fick. As this was the cafe, several prophylactics were fought for, when it got into large families; the common alexipharmic method with fnake-root drams I knew to prove ineffectual.

"The following feemed to be the only effectual prophylactic I ever knew tried, and which proved effectual in fifteen in one family, where none escaped without fome prefervative or another; and wherever it was duly complied with, the good effects of it were very evident. I obferved, that before the fever formed itself, the fure fign of a received infection, ready to difplay its tragical effects, was a fudden and unusual pain of the head, generally above one or both eyes, which in fome remitted with fhort intervals, and caufed a giddinefs or vertigo, rather than sharp pain, attended with an unusual feeblenefs and languor of the body, and often a ficknefs at the ftomach; thefe complaints, I obferved, were little regarded till the fever feized them very often all of a fudden, a few hours afterwards. Upon the first complaint of this pain of the head, they had fix or eight ounces of blood taken from the arm. Some fell into large sweats or plentiful breathings, foon after bleeding; by which their diforders went off: but thofe that did not fweat and their complaints continued, took a vomit of ipecacuanha foon after bleeding; and, the night after the vomit, fell into the like fweats, by the plentiful use of tepid diluents and warm covering. After these applications the diftemper never formed itself, as it ever did, when these complaints were neglected; although many had a brisk acute fever after, or in the time of their adminiftration, VOL. I.

C

for the space of twelve or twenty-four hours, of the fame nature with this fever when once formed; and all were lefs or more feverish in the time of their sweats, which, however, went off with them, and never returned.

"In all thofe, that were bled even in these circumstances, the blood was thin, watery, and feemingly diffolved, and that in winter; a very uncommon thing at that time of year in Virginia. Some few were feized fo fuddenly, as not to give room for this method of prevention; which, however, in most proceeded rather from inadvertency and neglect of a flight fudden diforder, for want of knowledge of what it meant, than from want of warning.

"In this manner we come to use emetics fafely in this disease, which are supposed to be neceffary by many, and fometimes much relied on; as they do indeed, when given time enough, help to prevent its worft fymptoms; although they are little lefs than fatal in them; fo that it may be truly said of them, what Celfus faid of bleeding in an apoplexy, They either kill or cure.'

"The bounds of this epiftle will not allow me to be particular about several remarkable things which occur in this disease; efpecially in the cure of it, and in the confideration of the different lædentia et juvantia; but I shall take notice of a few things indicated in the cure, which, if duly complied with, afford much relief at firft, and fecurity at laft, and which feem to be the chief, from which art feems to afford any confiderable and fignal affiftance to nature.

"The first and chief scope of the cure is to conquer the power of the disease, before it has produced any of its ill effects on the body, fo as to render it more mild and tractable, than it ufually is, when left to take its courfe; elfe the event will be precarious. The worst of these effects, and most to be dreaded and avoided, as we may learn from the above diffections and courfe of the disease, proceed from an inflammation of the vifcera. The principal way to prevent which, is generally found to be by large evacuations at first; so that the chief in

dication of curing this disease is the fame as in other inflammatory fevers, viz. to keep off any local inflammation, or more univerfal obftruction of the capillaries, by evacuations. Plentiful bleeding is a means commonly found moft effectual to obtain this end in the benign inflammatory fevers; but we cannot apply this most effectual remedy in this disease.

"There are but two paffages by which we can drain off the over-abounding ferum or diffolved blood, to wit, the outer or inner furface of the body by means of fudorifics or cathartics; for the evacuation by urine is uncertain, and not always in our power. Sweating takes place in this as in most other peftilential diseases. By this manner of evacuating, we can drain off the greatest quantities of the diffolved humours, and make the largest evacuation that can be fafely made, which feems to put a ftop to the violence of the fever, and danger of an inflammation; but it must be observed, that the heat of the medicine, which procures this evacuation, often fruftrates the good effects to be expected from it: for which reafon the fweats ought to be increased to fuch a degree, that the largenefs of the evacuation may cool the body more, than the medicine which raises them heats it; to which plentiful dilutions ought to contribute; for, from a neglect of these necessary cautions, this method of sweating often contributes to bring on an inflammation, when antiphlogistics are really indicated. Two things ought to be observed and duly complied with, to render this method of cure fafe and beneficial, and never detrimental or hazardous. 1. That there be no great diffolution of the blood, nor colliquation of the humours, when it is put in practice. 2. That the fpafms and conftrictions of the fibres, very remarkable and easy to be difcerned in this disease, and inflammation of the viscera, be not come on, when we give any heating fudorific medicine whatfoever. On this account it is, that this method of cure is not fo fuccessful in our cold winter and spring weather, when the humours are more fizy, the fibres more rigid, and the body more denfe and imperfpirable, by which we do not sweat so freely and plentifully as is neceffary; on which account I have known