ease, is of itself rarely, if ever, either the proximate or the occafional caufe. It accompanies, indeed, the greater number of diseases, and those of the most opposite characters; but it is obviously in general an effect only, and indicates nothing certain in regard to the cure. There is no doubt that the making it a primary object of confideration in practice, fo much as has been done of late, has been productive of much mifchief. General weakness is not always capable of being remedied by ftimulant and tonic remedies, nor by the ufe of rich and nutritious food; but often, indeed, by means the reverse of these, when fuch means are calculated to relieve or take off the original disease; as is not unfrequently the cafe. Nothing is more common than to observe, in topical inflammations, the action of the heart and arteries becoming ftronger after bloodletting, and the voluntary power at the fame time increased. In fuch cafes, bloodletting, by relieving the original difeafe, which had depreffed the powers of the system, becomes in reality a ftrengthening remedy. On the other hand, it is no lefs certain, that the use of ftimulating, or, as they are falfely called, ftrengthening remedies, by increasing the topical affection, often tends to deprefs the energy of

the fyftem ftill further, instead of roufing it*.

50. There seems, therefore, to be a real neceffity for making the diftinction mentioned, between general and topical affections; that we may not, in practice, be employed merely in the palliation of fymptoms, but in endeavouring to remove their causes, wherever this is practicable. There are ftill, no doubt, a number of morbid affections, which we are unable to refer to their proper and primary feat in the body; these ought, in the prefent state of our knowledge, to be confidered as anomalous, and as ferving to mark the imperfec

I fhall take this opportunity of remarking, that the doctrine which fuppofes almost all difeafes to be univerfal, and the whole fyftem to be acting in a fimilar manner, either in excefs, or the reverfe, owes any popularity it may have chanced to poffefs, more to its apparent fimplicity, than to its confonance with truth and the laws of the animal œconomy. In diarrhoea and dyfentery, which occupy a confpicuous place in the catalogue of afthenic difeafes, the part affected and the general fyftem are often in the opposite state of action, in regard to one another. The fyf. tem is weak; the intestines have all their actions preternaturally increased. This is feen in their augmented fenfibility and confequent pain; in the exceffive fecretions poured out into their cavity; and in their increased periftaltic motion: these furely cannot be confequences of local debility or a weaker action of parts. The fame contrast might be fhewn to exift in a great number of other difcafes, between the general fyftem and the feat of topical affection.

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tion of medical fcience. As this is improved, and obfervation becomes more accurate, the number of fuch anomalous affections may be expected to diminish. That this would be followed by beneficial confequences in practice, might be looked for with confidence. If we are incapable of discovering the intimate nature or rudiments of diseases (4), it is fomething at least to know their proper feats in the body our efforts to relieve them, by being more pointedly directed, will be more likely to be crowned with fuccefs. The old doctrine of revulfion taught us to attempt the relief of topical affections by applications to parts the most remote from the feat of difeafe: and this, doubtlefs, has fometimes its advantages. Obfervation, however, has evinced that, in many cafes, we can more effectually combat diseases, by attacking them at their fource to afcertain this, therefore, with certainty, is a matter of no fmall moment. Such an inquiry naturally precedes any inveftigation of the nature of difeafes, and must be fubfervient to it; for without knowing the feat of a difeafe, or the organ primarily affected, it is fcarcely conceivable that we should become intimately acquainted with its nature, or the beft poffible means of removing it.

CHAP. II.

OF THE PRIMARY SEAT OF FEVER IN THE BODY.

THERE is, perhaps, no disease that excites fuch general disturbance in the system, or deranges fo many of its functions, as fever properly fo called; hence its symptoms are numerous and complicated, and not eafily, in appearance, reducible to any certain order. It is little to be wondered at, therefore, that it should in general have been confidered as an univerfal disease, affecting effentially, at once or in fucceffion, every part of the system. This opinion of the nature of fever has been entertained in all ages, with very few exceptions; it has been infifted on by the latest and best writers on the subject; and is inculcated, I believe, by the most eminent teachers of the present day.

But I have endeavoured to fhew in the preceding pages, that neither this, nor any other difeafe, is juftly entitled to the denoPart I. D

mination of general or univerfal. With regard to fever, however numerous and diverfified its fymptoms are at times obferved to be, it will be found, on attentive examination, that few of these are essential, or belong to it exclufively, but are the greater part of them fecondary fymptoms only, and common to various other difeafes; or cafual, and of uncertain occurrence; depending not immediately upon the original and exciting caufe, but arifing out of fome previous fymptom, and many of them altogether the effect of adventitious circumftances, as climate, feafon, regimen, and the particular state and habit of body of the patient himself.

In attempting to affign the primary feat of fever, it will be neceffary to examine the various phenomena of the disease, to trace their order of occurrence, and their dependence on one another and on the exciting caufes. We fhall thus, if I mistake not, difcover the brain to be the true feat of morbid affection in fever, and the fource of all the fymptoms which effentially belong to it, and which ferve to distinguish it from other difeafes. This opinion will be confirmed by the confideration of the remote causes that induce fever, and of the particular circumstances which feem to predispose to it.