Blisters are of eminent service in cases of intestinal irritation, accompanied with tenderness on pressure; they will frequently also put a stop to obstinate vomiting, when other methods have failed of success.

370. The external application of heat to the region of the stomach will often allay gastric irritation that depends upon the presence of indigestible matter. The process of chymification is thus promoted by a species of contiguous sympathy that is not well understood.

371. The application of heat to the feet will be attended with the same beneficial consequences: this connexion is still less apparent, but it is a fact, no less remarkable than true, that the digestion of a person in health may be arrested by the sudden application of cold to the lower extremities.

372. The use of friction, when applied by means of the flesh-brush to the abdominal region, deserves a dislanguished place in the catalogue of dyspeptic remedies. I have usually directed its application for a few minutes, night and morning, and the most obvious benefit has arisen from it. The ancients are well known to have held friction in high estimation, not only in the cure, but for the prevention of disease. The moderns have unwisely suffered the practice to fall into disuse. If it were necessary to illustrate the utility of friction, we have only to adduce the well known effects which are produced on horses by the operation of currying; and which can alone depend upon freeing the surface from the recrementitious part of the perspirable matter, and promoting a due circulation in the skin. In thus making them sleek, they become more gay, lively, and active, and will preserve their strength with half the quantity of food, than when it is given to them without such assistance. In cases where the application of cold may be considered useful, the brush may be immersed in equal quantities of vinegar and water.

373. With respect to the utility of wearing flannel next the skin, some diversity of opinion has existed. Its advantages consist in gently stimulating the surface, promoting perspiration, and conveying away the moisture as it may be deposited. When worn only in the day it does not appear objectionable, but is, on the contrary, salutary to those whose skin may be supposed to require such a stimulant; but I agree with Dr. Beddoes in -believing that no good reason can be assigned why any one, who is the master of a comfortable bed, should wear it during the night. In that state of increased sensibility of the skin which sleep induces, it is more likely to be injurious than at any other time, by the stimulating effects of its piles, and by the warmth it keeps collected round the body. There is also another objection to its use, under such circumstances: the perspirable matter, by accumulation, undergoes a chemical change, and the skin is thus, as it were, immersed in a noxious atmosphere. For the same reason, the flannel should be frequently changed.

I have generally preferred, in dyspeptic cases, the uses of a flannel stomacher, or a piece of loose flannel worn over the stomach and bowels during the day, and which may be thrown off at bed-time.

374. The use of cold and warm bathing offers another subject for consideration. The advantages arising from it, in the treatment of dyspepsia, are indisputable; but its application requires skill and prudence. When we consider the functions of the skin, in their relations to the digestive process, we cannot be surprised that an improvement in the state of the former should confer a corresponding benefit on the latter. The cold bath appears eminently serviceable to those who are suffering from dyspepsia, induced by the enervating modes of life peculiar to great towns, or by great mental exertion. Where, however, there exits considerable biliary disturbance, it generally does harm. It is. also a matter of great consequence to ascertain the strength of the patient, and whether his vital energies are sufficient to produce that re-action, without which the cold bath must ever prove a source of mischief. This circumstance must likewise direct us in appointing an appropriate period for the operation. The robust and healthy may bathe early in the morning, or before breakfast, without the least hesitation; but the dyspeptic invalid should never venture into the water until his stomach has been stimulated by a slight meal.

The period best calculated for immersion is about two hours after breakfast, which will enable him to take some previous exercise; he ought never to feel any degree of chilliness, but should be rather warm than cool, before he attempts to bathe. Dr. Currie has justly observed, "that persons ought not to wait on the edge of a bath, or of the sea, until they are perfectly cool, for if they plunge into the water in that state, a sudden and alarming chilliness may be expected, which would not have been the case had they been moderately warm when they went into the water." There exists a popular belief that, unless a person plunges head foremost, an accumulation of blood may take place in the brain. There is no truth in this observation. A sudden plunge is a violent and unnatural exertion, and if the patient has not strong powers of re-action, it may be followed by unpleasant consequences. The shock thus given to the nervous system may, like a blow on the head, produce syncope. A case occurred at Brighton, in which a person in a state of debility died suddenly from the shock of a shower-bath. .

375. An invalid should never remain longer than two minutes in the water, and the body should be kept during the whole time under the surface. If, instead of a genial glow, chilliness, languor and headach follow, we may conclude that the vigour of the system is not equal to create and sustain that re-action upon which the benefits of bathing must depend, and the practice should be immediately abandoned. It is, I think, generally advisable for invalids to bathe only on alternate days, until they find their strength so much increased as to allow them, without risk, to indulge in it daily.