It has been generally supposed that their dryness affords a proof that the nutritive part of the aliment has been duly absorbed; and there can be no doubt that such motions, if their colour be natural should be considered as favourable in cases of indigestion. Boerhaave has remarked, that "people who complain of going too seldom to stool, and of voiding hard and dry faeces, complain without reason, because this proves the strength of their constitution." The least favourable consistence is that of a soft pudding, especially if the discharge of the motion be unattended with a feeling of relief corresponding with the quantity evacuated; a sensation of something being retained, accompanied with that of a bearing down in the lower portions of the intestines, is not unusual upon such occasions. There is a peculiar appearance connected with this species of evacuation, which, I believe, has never been described in any work, nor indeed is it easy to convey by words its exact nature. It was first pointed out to me by Dr. Baillie, and I have since noticed it in numerous instances, and become satisfied of its immediate connexion with diseased secretion.

The consistence of the motion is that of a pudding, but it is of unequal density in its different parts, and exhibits a surface as if it had been rasped by a file. I have still another form of faeces to describe, which would seem to depend upon a contraction of the intestine; the excrement is hard, but having a diameter not much exceeding that of a tobacco-pipe. In protracted cases of dyspepsia, the occurrence of this appearance has given origin to a belief in the existence of stricture in the rectum; but I believe its cause is always seated in the higher portions of the large intestines. In order that we may deduce safe conclusions from the appearance of a faeculent discharge, we must be well acquainted with the nature and extent of the change which may be produced upon it by the operation of different aliments and medicines. The air, too, has the effect of altering the colour, for which reason it should be examined as speedily as may be convenient. This observation applies with great force to the stools of infants, which, although perfectly yellow when voided, rapidly assume a green appearance; a fact which would seem to arise from the decomposition of the bile.

340. Certain green vegetables, especially spinach, impart to the faeces a green hue, which may be mistaken for vitiated bile. Beet-root will also give a colour to the alimentary discharge, which it is necessary to distinguish. Persons who take a considerable quantity of milk will pass pale-coloured evacuations, as if the bile were imperfectly secreted. Where the aliment has been of a very complicated description, the faeces will generally assume a crude and diversified character, owing, probably, to the several parts not having undergone the same degree of digestion, as already explained. Where much stimulant drink has been used, and the person has been subjected to long fasting, or much labour, or has perspired profusely, the faeces acquire a hardened character. It is essential for the practitioner to know, that certain parts, both of animal and vegetable substances, pass through the body without undergoing any change: this is the case with the skin and seeds of fruits, etc. Cheese is also very apt to pass in an undigested state.

Dr. Marcet records an instance of this kind, in which the substance was at first mistaken for an intestinal concretion; but it proved to be either a piece of cheese formed into a ball by the action of the intestines, or a portion of caseous matter actually formed in the intestines, from milk taken as nourishment by the patient, and coagulated by the gastric juices into an undigestible mass. This latter supposition is the more probable, as Dr. Wollaston, a few years afterwards, had several concretions of the same kind brought to him for examination by a medical practitioner, and which proved of the same nature, and had been discharged by a patient whilst using a milk diet. It has also been stated by Dr. Marcet, that concretions of oat seeds are not unusually passed by the inhabitants of Scotland and Lancashire, where the oatcake is in common use as an article of food amongst the lower classes. The spawn of lobsters, a very indigestible substance, has also occasioned similar deception. Magnesia, when repeatedly taken, will, by the assistance of a little animal mucus, become consolidated into masses of formidable magnitude.

Mr. E. Brande has recorded an interesting case of this kind in the first volume of the Journal of the Royal Institution. The influence produced by certain medicines upon the colour of the faeces is equally striking; iron and bismuth have the property of tinging them black, and magnesia of giving a white appearance. We see, therefore, the importance of attending to such circumstances, where it is an object to ascertain the state of the biliary secretion from the colour of the stools; and it would be judicious, on such occasions, to restrict patients to a diet that is not likely to colour the faeces.

341. The quantity of faeculent discharges is also an important object of enquiry; and in estimating it, we must always consider it with reference to the nature as well as quantity of the food. I have known persons who have lived for some time on the fat of veal, marrow, etc. for the purpose of obtaining nutriment with the least possible quantity of excrement, in order to avoid irritation in a diseased rectum, and it is surprising bow scanty the evacuations have been on such occasions. Rice scarcely leaves any excrementitious matter to be transmitted along the intestines, and hence has arisen the idea of its astringent quality. Fish, on the contrary, leaves a large quantity of excrement.

Some of my readers may perhaps consider the observations which I have been induced to offer upon the appearances of the feculent discharge as unnecessarily minute; but I am anxious to urge upon every practitioner the absolute necessity of such inspections. No one can successfully conduct the treatment of a severe dyspeptic complaint unless he submits to the performance of such a duty. All the great physicians of antiquity relied upon such a source of information for their guidance. Hippocrates carried the practice to such an extent as to have acquired from some of the wits of his age the appellation of333 Animal Heat Part 2 3 as Arisphanes had before named Esculapius. Some modern practitioners have, from the same scrupulous attention, been obnoxious to a similar charge; but I trust that no physician will be induced to swerve from the performance of a paramount duty by such intimidation 1.