the common idea is well founded, that cold applied to the head itself is more effectual in reftraining immoderate action in the veffels of the brain, than when applied to more distant, though more fenfible, parts. The fcalp is (from habit) one of the most infenfible parts of the body, with regard to the impreffion of cold: while we know that the full operation of this agent on the brain can be produced by its application to remote parts of the fyftem.

A confiderable difference is obferved in the effects of cold, according as its application is fudden and intenfe, or more moderate and long continued. In the former cafe the effect is greater, but at the same time is com→ monly tranfitory; and very often the parts whofe actions were fuppreffed or diminished while under the influence of the cold, act afterwards with greater energy than before. This is what is called the re-action of the fyftem, and takes place equally with regard to the three feries of actions before mentioned; which feems to fhew that the primary change induced in each cafe is the fame, viz., a diminution of vafcular action. Thus the paleness and fhrinking of the furface,—the diminished energy of the functions of the brain, and the reduced action of the heart

and arteries, which follow the temporary application of the cold bath, are fucceeded by an unusual glow on the furface, increased mufcular vigour, and a strong and full pulse.

When cold is applied in this sudden and tranfitory way to parts already in a state of inflammation, the re-action which fucceeds to the previous ftate of torpor fometimes aggravates the disease; as in the cafe of burns, which are relieved from pain by a temporary application of cold, but if this be foon withdrawn, the pain returns with greater violence than before. And in order to produce permanent benefit in this cafe, the application of cold must be continued till the difpofition to increased action afterwards ceafes; an effect which, in the cafe of burns, often requires a period of many hours to accomplish.

We are now, I flatter myself, prepared in fome measure to comprehend and estimate the value of cold as a remedy for fever, a remedy concerning which, and its mode of acting, many doubts and difagreements among practitioners ftill fubfist. I fhall not enter further into the history of the subject, than to observe, that the practice is of

ས་ ་

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great antiquity, though modern writers have contended for the honour of the discovery.

Cold has been employed in two very different ways, in the cure of fever; the one, its fudden but temporary application, as by the cold bath or the affusion of cold water over the body;-the other, the gradual and long-continued exposure of the patient to cool air, the washing the furface of the body or limbs with cold or tepid liquids, and the exhibition of cool drinks.

In the former way, it feems to act by its fudden impulfe, and not by the mere abftraction of heat from the body, as Dr. Currie feems to have fuppofed. In this refpect, it ranks with emetics, mental emotions, and other fudden and violent impreffions, which are found occafionally to interrupt the progress of fever, and many other difeafes. The effect of the application in this cafe is almost immediate. The disease has been often thus cut fhort at once. difpofition to fleep and fweating has fucceeded, and the patient has awoke almost free from disease.

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By the other mode of applying cold in fever, viz., by exposure to cool air, the ufe

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of cold drinks, and fpunging the furface with cold or tepid liquids, the preternatural heat of the body is gradually abstracted, and thus the most prominent fymptom is relieved. But it is not by the fimple abftraction of heat from the body that this mode of cure produces its good effects in fever; but by the reduction of vascular action ; firft in the fkin; fecondly in the brain, by fympathy; and, laftly, in the general fyftem. Thus the action is destroyed upon which the excess of heat (which is merely a fymptom) depends.

It has been for many years a practice with Dr. Gregory, the present eminent Profeffor of the Practice of Phyfic in Edinburgh, in addition to the exposure of the patient to cool air in typhus, to direct the whole body to be washed with a fponge dipped in cold vinegar and water; with the effect of reducing the pulfe, in many cafes, from 110 to 90 ftrokes in a minute. This fact is not difficult to be understood, when it is confidered that the fkin is an organ of fenfe, and therefore intimately affociated with the brain; and that by inducing torpor in the one we diminish the energy of the other, and, fubfequently, the irritated vascular action of the whole fyftem.

With regard to the comparative merits of the two modes mentioned of applying cold in fever, we must appeal to experience. The affufion of cold water, or the cold bath, fo ftrongly inculcated of late by Dr. Currie, in his valuable publication on the fubject*, has fo often fucceeded in immediately arresting the progrefs of fever, as proved by his own experience as well as that of many other unprejudiced obfervers, that the practice appears to merit more attention than it has yet received.

It is to be observed, however, that neither this, nor any of the other remedies employed in the cure of fever, effects its purpofe with certainty; and it confequently becomes a question of no fmall moment to determine, whether in cafe of failure the patient is put into a worse situation with regard to the future progrefs of the disease, than if no attempt had been made to cut it fhort. This point, I think, we have scarcely yet grounds for determining satisfactorily.

If we rely implicitly upon the reports which have been hitherto made on the fub

* Reports on the Effects of Water, cold and warm, in the Treatment of Fevers: by William Currie, M.D.