ever, is no argument against its Specific operation; for calomel frequently induces falivation, at the time that its purgative effects are most confpicuous; as I know by repeated obfervation.

It has been remarked by feveral of those who have employed mercury in the cure of fever, that its good effects were always moft apparent when falivation took place, an effect that it was often found exceedingly dif ficult to bring about. But neither is this decifive of the question. For in the worst. cafes of fever, it could not, in the largest dofes, be brought to affect the mouth, fo extreme was the torpor induced by the dif eafe; while in milder cafes the mercury was found to exert its ufual action. The appearance of falivation, therefore, and the cure of the fever afterwards, might be only indications of a milder ftate of disease*.

It is, however, I think, moft probable

*It is certain that the fyftem, in malignant fever, is often, to an astonishing degree, infufceptible of the action of mercury, and various other ftimuli: and I do not fee how this extraordinary torpor is to be explained, but uponthe principle I have laid down, of a topical derangement of the fenforium. Such a condition of the system, we well know, is induced by hydrocephalus, a difeafe that owes its origin to inflammation in the brain.

upon the whole, that mercury, when freely and repeatedly administered, operates with advantage in the cure of fever, both as an evacuant, and by its fpecific powers. We fee that, on fome occafions, it exerted little or no evacuant effect; and the fublimate, which is not remarkable for its purgative properties, was found to be attended with the fame advantage as calomel.

Mercury certainly exerts peculiar effects, on the brain; and it is probably through the influence of the brain, thus irritated, that the general febrile ftate is produced which is fo commonly obferved under the free use of mercury, and not by the immediate application of the medicine to the heart and general vafcular fyftem. Dr. Adams, remarking on its use in the cure of Syphilis, fays, "the fever it produces may be truly called fpecific, from its uniformity and total difference from all others*.'

Moderately used, mercury often relieves headach depending on local increased vafcular action; and it is confidered as specific in the cure of that variety of inflammation of the brain or its membranes, which is impro

*Effay on Morbid Poisons, 4to, p. 86, 2d edit.

perly called hydrocephalus. It has often, alfo, removed gutta ferena, epilepsy, and other fenforial affections. Employed fo as to excite falivation, it has frequently contributed to the cure of obftinate intermittents, by rendering them obedient to the Peruvian bark*, which they had before refifted; and it fuperfedes various other dif eases that are kept up by an acquired habit.

When mercury is carried to excess, it produces headach, general-debility, incapacity for mental exertion, and, finally, mania; effects that very clearly demonstrate its influence on the fenforium. We are prepared, therefore, to expect that it will be hereafter reforted to with more confidence as a remedy for fever; though, as happens with regard to most others, we have yet much to learn of the circumftances which fhould in all cafes govern its administration.

* Dr. Donald Monro, Medical Transactions, vol. ii, p, $25.

Sect. XII.-----Of the Natural Cure, or Spontaneous Termination, of Fever.

AFTER all that has been faid refpecting the cure of fever by the different methods pointed out above, it is not to be overlooked that fever has a strong difpofition to terminate fpontaneously after going through certain ftages; and hence that the effects of remedies are liable, on many occafions, to be falfely eftimated. This tendency is fo remarkable, that many phyficians have chofen to rely on it for a cure, and have diffuaded from all artificial means of bringing the disease to a crisis, preferring to leave the business altogether to nature. Others, again, deny the power of medicines to cut fhort the progrefs of fever, and think that phyficians deceive themselves, by afcribing effects to caufes that have in reality little or no influence on their production.

Dr. William Brown, one of the furgeons to the Royal Infirmary of Edinburgh, in a paper published in Dr. Duncans' Annals of Medicine for 1802, entitled Obfervations

on

the Duration and Course of Fever in Bri

tain, and on the Efficacy of Medicine in interrupting its Courfe, and fhortening its Duration,' endeavours to fhew, from the records of the Infirmary, that medicine has not the effect of putting a fpeedy termination to fever; and he even thinks it proved, by the fame evidence, that the disease was not at all fhortened by the medicines applied.

Out of 280 inftances registered, which he particularly examined, only twelve were marked, in which the fever ceased on the day that medicine was firft applied; viz., one on the 5th, one on the 6th, four on the 7th, one on the 8th, one on the 10th, and three on the 13th day of the disease. In the three first days after admiffion, 71 cafes of remiffion took place; which is only one in four. And of the whole number of cafes, (280), it appears that only 159 were cured within the period of fix days after the application of medicine was begun.

Thefe facts, however, go only to prove, that when the course of fever is once established in the fyftem, and the disease has proceeded for a certain number of days, it is exceedingly difficult to interrupt its progrefs by the ordinary means of cure. This has been at all times known to practitioners, and