200. The marks of the good effects of such a fomentation, are, the patient's bearing it easily, its relieving aclirium, and inducing sleep.

201. Having now considered the several means of satisfying the first general indication in the cure of fevers, i proceed to the second, (126), which is, to remove the cause, or obviate the effects, of debility.

202. Most of the sedative powers inducing debility, cease to act soon after they have been first applied; and therefore, the removing them is not an object of our present indication. There is only one which may be supposed to continue to act for a long time; and that is, the contagion applied: but we know nothing of the nature of contagion that can lead us to any measures for removing or correcting it. We know only its effects as a sedative power inducing debility, or as a ferment inducing a tendency to putrefaction in the fluids. The obviating the latter will be considered under our third general indication, and the former alone is to be considered here.

203. The debility induced in fevers by conta gion, or other causes, appears especially in the weaker energy of the brain; but in what this consists, or how it may be directly restored, we do not well know. As nature, however, does, seem

ingly for this purpose, excite the action of the heart and arteries, we ascribe the continuance of debility to the weaker reaction of the sanguiferous system; so that the means to be employed for obviating debility, are immediately directed to support and increase the action of the heart and arteries; and the remedies used are TONICS or STI

MULANTS.

204. In contagious diseases, both from the effects which appear, and from dissections, it is known that the tone of the heart and arteries is considerably diminished; and that tonic remedies, therefore, are properly indicated.

These are to be considered as of two kinds; the first being the power of cold, the second that of tonic medicines.

205. The power of cold, as a tonic, I have mentioned above, (90); and it is employed in fevers, in two ways; either as the cold matter is thrown into the stomach, or as it is applied to the surface of the body.

206. As it has been shewn above, that the tonic power of cold can be communicated from any one part to every other part of the system; so it will readily be allowed, that the stomach is a part as fit for this communication as any other; and that

cold drink, taken into the stomach, may therefore prove an useful tonic in fevers.

207. This the experience of all ages has confirmed but, at the same time, it has been frequently observed, that, in certain circumstances, cold drink, taken into the stomach, has proved very hurtful; and, therefore, that the use of cold drink in fevers requires some limitations. What these limitations should be, and what are all the circumstances which may forbid the use of cold drink, is difficult to determine; but it seems clearly forbidden, in all cases where a phlogistic diathesis prevails in the system, and more especially when there are topical affections of an inflammatory nature.

208. The other method of employing cold as a tonic, is, by applying it to the surface of the body. The application of cold air to the surface of the body, as a refrigerant power fit to moderate the violence of reaction, I have spoken of above (133); but probably it may also be considered here as a tonic, and useful in cases of debility.

209. Not only cool air, but cold water also, may be applied to the surface of the body, as a refrigerant, and perhaps as a tonic. The ancients frequently applied it with advantage, to particular

parts, as a tonic; but it is a discovery of modern times, that in the case of putrid fevers, attended with much debility, the body may be washed all over with cold water.

210. This was first practised at Breslaw in Silesia, as appears from a dissertation, under the title of Epidemia verna que Wratislaviam, anno 17, afflixit, to be found in the appendix to the Acta Nat. Curios. vol. x. And from other writers we find, that the practice has passed into some of the neighbouring countries; although in this island, so far as I know, we have hitherto had no experience of it.

211. The medicines which have been employed in fevers, as tonics, are various. If the saccharum saturni has been found useful, it is, probably, as a tonic, rather than as a refrigerant; and the ens veneris, or other preparations of iron which have been employed, can act as tonics only. The preparations of copper, from their effects in epilepsy, are presumed to possess a tonic power; but, whether their use in fevers be founded upon their tonic or their emetic powers, may be uncertain. The use of arsenic and of alum, in intermittent fevers, seems manifestly to depend upon their tonic power. And, upon the whole, there may occur cases of continued fevers, which may be cured by tonics taken from the fossil kingdom; but the use

of these has been rare, as well as the effects uncertain; and physicians have employed, more commonly, the vegetable tonics.

212. A great variety of these has been employed in the cure of intermittent fevers; but how many of them may be employed in continued fevers, or in what circumstances of these fevers, is not well ascertained; and I shall now only consider the question with respect to the most celebrated of these tonics, the Peruvian bark.

213. This bark has been commonly considered as a specific, or as a remedy of which the operation was not understood. But it is certainly allowable to inquire into this matter; and I apprehend may be explained.

it

214. To this purpose it is to be remarked, that as, in many cases, the effects of the bark are perceived soon after its being taken into the stomach, and before it can possibly be conveyed to the mass of blood, we may conclude, that its effects do not arise from its operating on the fluids; and must, therefore, depend upon its operating on the nerves of the stomach, and being thereby communicated to the rest of the nervous system. This operation seems to be a tonic power, the bark being a remedy in many cases of debility, particularly in gangrene and, as the recurrence of the parox