The degree, uniformity, and equable diffusion of heat are circumstances of importance: they will enable us to form some estimate of the state of the vital powers generally; and when we consider what an intimate connexion subsists between the temperature of the body and the different stages of digestion, it will throw some light upon the comparative energy with which they are performed.

334. With regard to the indications afforded by the state of the appetite for solids or liquids, I have already delivered my opinions.

335. The appearance of the tongue has also been noticed in the preceding pages of this work; it is natural to expect that a part, which is so immediately connected with the functions of the stomach, should be the first to exhibit a deranged condition in dyspepsia, and we accordingly find this to be the case. Baglivi has said that the pulse may deceive you, but that the indication afforded by the tongue is infallible. It greatly varies, however, in appearance, in different cases, and in different stages of the same case. When white and milky, it announces general irritation, frequently from mental causes. When brown or dark-coloured, foul congestions in the prima vine, or the presence of vitiated secretion; and when unusually bright and shining, a morbid condition of the villous coat of the stomach or intestines, which is usually associated with, or is the precursor of, organic mischief; for it indicates the presence of a degree of fever not commonly excited by the simple functional aberrations of the digestive organs.

In some cases the tongue is comparatively clean, but its cuticle loses its natural hue and natural transparency, and presents a sodden appearance: this generally depends upon the secretions having been for a considerable length of time in an unnatural state.

336. There is a phenomenon connected with the appearance of the tongue of much importance in its indication, and which, as far as I believe, has been so little noticed, that I am anxious to call the particular attention of the practitioner to its nature. It is a dirty brown fur principally occupying one half of the tongue, longitudinally from its root to its tip. I believe that such an appearance may be very generally received as an evidence of cerebral disturbance. In paralysis it is frequently very striking, but in morbid states of the nervous system, short of such mischief, I have noticed its presence in a less defined form, and have found the conclusion deduced from it subsequently confirmed by other symptoms.

337. The salivary secretion is susceptible of various morbid conditions, to which the labours of the animal-chemist have not hitherto been directed; it is sometimes unnaturally ropy or viscid, so as to occasion an incessant hawking; at other times it is so preternatu-rally thin and copious, as to be discharged from the mouth in considerable quantities. I have lately seen a dyspeptic patient who declares, that his pillow is thoroughly wet in the morning with the discharge which takes place during the night; and yet dryness of the mouth, and a parched tongue, are amongst the most disagreeable of his symptoms, as if the secretion had lost the power of lubricating the parts to which it is applied. Frank states that he has known the saliva, when secreted in unnatural quantities, to have become saccharine.

338. The state of the cutaneous discharge is a circumstance of more importance than physicians usually assign to it. The reciprocal connexion which subsists between the functions of the skin and stomach is so obvious, that if the latter be deranged, the former is immediately affected, and vice versa. It is the change produced upon the skin which assists in bestowing that peculiar physiognomy so characteristic of protracted indigestion; and amongst the most useful remedies in this disease, will be found those which are calculated to restore the healthy action of the cutaneous organs. When we remember that a person in health who takes eight pounds of aliment during the twenty-four hours, will discharge five of them by perspiration, we shall readily perceive how greatly the suspension or derangement of such a function must burden the digestive organs.

339. The condition of the excretions, as to quantity and quality, is another object of important inquiry. I shall first describe the different appearances which the faeces may present in the various cases of chylopoietic disturbance. On some occasions they will contain an excessive quantity of bile; on others they will not be sufficiently tinged with that secretion, and will therefore assume a light yellow, or a clay-brown colour. They will sometimes more particularly indicate by their appearance the presence of vitiated secretion, and have a dark olive, or a blackish-brown hue. In some cases they have so far degenerated as to resemble pitch. The gall-bladder frequently discharges highly concentrated and acrid bile, scalding the anus during its passage. Where the biliary secretion has been irregularly supplied, the faeces may assume a partially coloured appearance. It is not unusual to notice mucous and gelatinous matter accompanying, but not mixed with the faeces, and which have been sometimes mistaken for worms. It must have derived its origin from the alimentary membranes, or from the glands situated in the canal. There is a very peculiar morbid evacuation which I have occasionally witnessed, and which has been described as resembling yeast in colour and consistence.

This frequently comes on suddenly, and as suddenly departs; it is generally very profuse in quantity, and is usually preceded by uneasy sensations in the alimentary canal. It would appear to be a morbid secretion of the intestinal juices during a torpid state of the liver: although in one case, in which I witnessed its occurrence, it was evidently connected with a diseased state of the pancreas. I may, in this place, take notice of the appearance of fat-like lumps of matter which are sometimes passed from the intestines. I suspect that they are inspissated portions of mucus from the caecum; I have, at least observed such evacuations to be accompanied by pain in that region. In most eases of dyspepsia, the stools will contain portions of undigested food, showing at once the failure of the assimilating powers. The odour of the discharge is a circumstance of importance; a fetid stool indicates less permanent or extensive change, than one which is deficient in the characteristic odour, and yields a faint smell. The consistence of the faeces will likewise be found to afford some useful signs.