185. With respect to the manner of administration, that of the calx nitrata is simple, as the whole of what is judged a proper dose is given at once, and no more can properly be given till the time of the next accession.

The administration of the emetic tartar is dif ferent. It is to be given in small doses, not sufficient to excite vomiting; and these doses, after short intervals, are to be repeated for several times, till sickness, nausea, and some, but not much, vomiting, come on. The difference of this administration must depend upon the dose, and the length of the intervals at which it is given. If it be intended that the medicine should certainly operate by stool, the doses are made small, and the intervals long. On the contrary, when vomiting is proper, or when much purging ought to be avoided, and therefore some vomiting must be admitted, the doses are made larger, and the intervals shorter.

186. With respect to both kinds of preparations, the repetition is to be made at the times of accession, but not very often. For if the first exhibitions, duly managed, have little effect, it is seldom that the after exhibitions have much; and it sometimes happens that the repeated vomitings, and especially repeated purgings, do harm by weakening the patient.

187. The other set of internal medicines,

(152, 2), which I suppose may be useful in taking off the spasm of the extreme vessels, are those named antispasmodic. How many of these may be properly employed, I am uncertain; and their mode of operation is involved in great obscurity. It is certain, however, that opium, camphor, musk, and perhaps some others, have been employed in fevers with advantage; but the circumstances in which they are especially proper and safe, I find difficult to ascertain; and therefore cannot venture here to lay down any general doctrine concerning them.

188. The external means (151), suited to take off the spasm of the extreme vessels, are BLISTERING and WARM BATHING.

189. What are the effects of blistering, so frequently employed in fevers, is not yet agreed upon among physicians; and many different opinions have been maintained on this subject, drawn not only from reasoning, but also from presumed experience. I must not, however, enter into controversy; but shall deliver my own opinion in a few words.

190. I am persuaded, that the small quantity of cantharides absorbed from a blistering plaster, is not sufficient to change the consistence of the mass of blood and therefore that such a quantity can

neither do good, by resolving phlogistic lentor, if it exists; nor do harm, by increasing the dissolution of the blood arising from a putrid tendency in it. I therefore neglect entirely the effects of cantharides upon the fluids.

191. The inflammation produced by the application of cantharides to the skin, affords a certain proof of their stimulant power: but, in many persons, the effect of that stimulus is not considerable; in many, it is not communicated to the whole system; and, even when the effect does take place in the whole system, it seems to be taken off, very entirely, by the effusion and evacuation of serum from the blistered part. I conclude, therefore, that neither much good is to be expected, nor much harm to be apprehended, from the stimulant power of blistering, and the certainty of this conclusion is established, by the great benefit arising from the proper practice of blistering in inflammatory diseases.

192. Much has been imputed to the evacuation occasioned by blistering; but it is never so considerable as to effect the whole system; and therefore can neither, by sudden depletion, relax the sanguiferous vessels, nor, by any revulsion, affect the general distribution of the fluids.

193. The evacuation, however, is so consider

able as to affect the neighbouring vessels; and the manifest utility of blistering near the part affected, in inflammatory diseases, leads me to believe, that blistering, by deriving to the skin, and produ cing an effusion there, relaxes the spasm of the deeper seated vessels. I apprehend it to be in this manner that the tumor of a joint, from an effusion into the cellular texture under the şkin, takes off the rheumatic pain affecting that joint.

194. Analogous to this it may be held, that the goods effects of blistering in continued fevers, arise from its relaxing the spasm of the extreme vessels, by a communication of the blistered part with the rest of the skin; and this is illustrated by the ef fect of blistering in colic and dysentery.

195. It appears to me, that blistering may be employed at any period of continued fevers; but that it will be of most advantage in the advanced state of such fevers, when, the reaction being weaker, all ambiguity from the stimulant power of blistering is removed, and when it may best concur with other circumstances tending to a final solution of the spasm.

196. From the view of this matter given in 193, and 194, it will appear, that the part of the body to which blisters ought to be applied, is indifferent,

excepting upon the suspicion of topical affection, when the blistering ought to be made as near as possible to the part affected.

179. Whether SINAPISMS, and other RUBEFACIENTIA, act in a manner analagous to what we have supposed of blistering, may be doubtful; but their effects in rheumatism, and other inflammatory diseases, render it probable.

198. The other external means of taking off the spasm of the extreme vessels, is warm bathing. This was frequently, and in various circumstances, employed by the ancients; but till very lately has been neglected by modern physicians. As the heat of the bath stimulates the extreme vessels, and, with the concurrence of moisture, also relaxes them, it seems to be a safe stimulus, and well suited to take off the spasm affecting them.

199. It may be applied to the whole body by immersion; but this is, in many respects, inconvenient; and whether some of the inconveniencies of immersion might not be avoided by a vapourbath, I have not learned from experience. I know, however, from much experience, that most of the purposes of warm bathing can be obtained by a fomentation of the legs and feet, if properly admi nistered, and continued for a due length of time, which ought not to be less than an hour.