Pepsin is one of the normal constituents of gastric juice, and, with the assistance of hydrochloric acid and of lactic acid, or both, it constitutes the most important solvent of the nitrogenous portions of our diet. If this constituent be insufficiently secreted, the solution of food is imperfect, and it must remain undissolved or be taken in a smaller quantity; and the object for which pepsin is administered medicinally is to promote artificially the solution of fleshy portions of food. Thus it was introduced by Corvisart, and into England by Dr. Ballard. It has been extensively used, and many have spoken very highly of its beneficial effects; but these encomiums we can scarcely endorse, for when the vaso-motor nerve acts inefficiently, and the appetite is lost, it is far better to seek to restore these than to supply the lacking energy by extraneous help.

The gastric juice contains lactic and hydrochloric acids, which, with the pepsin, constitute the most important chemical principles of the medium by which solution of the food is accomplished. It has been proposed to promote the digestive process by the addition of these acids. For a long period hydrochloric acid, in its dilute state, has been employed, and we have. frequently noticed its beneficial effect; but we find that its good result is due, not only to the chemical reaction of the hydrochloric acid as increasing the gastric solvent power, but to the effect upon the system generally, and to its local action upon the mucous membrane. Hydro

chloric acid is invigorating to a degree beyond that which is explained by its mere acidity.

In this respect it differs from lactic acid and other lactates as medicinal agents. They are merely excretory in their character, and it is doubtful whether the lactic acid found in the stomach is really an essential ingredient. Lactic acid is abundantly produced in the secondary chemical changes which organic compounds of the food undergo, and is not in itself a beneficial and tonic medicine. Hydrochloric acid is of service in those Linstan instances especially in which we find digestion very slow, the appetite poor, the tongue large, clean, and marked by the teeth; the food often remains in the stomach partially digested, and a sense of weight or painful distension from secondary chemical change is the result. The acid, then, tends to promote solution when given soon after a meal; but in these cases, even (when given independently of food, its action is service(able, for it appears to strengthen and invigorate the vaso-motor nerve. The lactates are of no service in this respect, and they tend after their absorption to oppress the system rather than to invigorate.

The pancreatic secretion exerts an important change upon the oleaginous substances in the chyme, and, according to M. Corvisart, it acts upon the nitrogenous also; and pathological observations tend to confirm the opinion that the secretion from the pancreas, being of an alkaline character, serves, by its combination with

the elements of oleaginous food, to promote their absorption into the system. In strumous disease, and in some forms of phthisis, fat is with difficulty assimilated, and the greatest benefit is observed to follow the administration of an oil easy of assimilation, such as cod-liver oil. Dr. Horace Dobell traces the proximate cause of phthisis, &c., to some imperfect action of the pancreas, and has proposed that an emulsion should be formed from the pancreas of lower animals, and thus used that it may promote the absorption of fatty portions of food.

This remedy may be placed in the same category with the secretion from the liver, as given in the form of inspissated bile. Bile naturally acts as an aperient; it retards fermentative changes, and when from numerous causes the liver seems to act inefficiently, and the bowels are confined, it has been proposed as a substitute for the natural supply. These remedies are one step in advance of the philosophical remedy of phosphorized oil when the brain substance is defective.

3. A third class of remedies in gastric disease are those which remove the impediments of digestion; but these will be noticed especially in the consideration of the different forms of dyspepsia. A state of active or of passive congestion of the mucous membrane interferes with the healthy secretion of the gastric juice, and hus prevents normal digestion; or the mucous membrane comes so intensely irritable that it cannot tolerate the

presence of food; and to lessen this sensibility is to take away a great hindrance to the normal work of the stomach. Again, the secretion may become of an unhealthy character from other disease, such, for instance, as in Bright's disease of the kidneys, when the gastric juice contains urea; or direct pressure may be exerted upon the stomach, so that the requisite expansion and movements cannot be executed; and lastly, fermentative changes are in some instances induced in the semi-digested mass, gaseous and acid products are formed, and numerous distressing symptoms are the result. It is our object to ascertain what are these impediments to the healthy exercise of functional energy, and if possible to remove them. It is not by the blind treatment of any mere symptom that we can effectually do this, but rather by the removal of the causes themselves, although we may be compelled by the urgency of some particular symptom to make its relief the primary object of treatment.

Alkalies are given to diminish irritability, especially soda and potash, so also magnesia and lime in solution, nitrate of bismuth, nitrate and oxide of silver, and, at Dr. Leared's suggestion, the black oxide of manganese. Sometimes anodyne and anti-spasmodic remedies assist materially in diminishing this same abnormal sensibility-morphia, opium, henbane, belladonna.

Active and passive congestions are relieved by mer

curials, which stimulate the glandular organs generally, and act upon the bowels, thus unloading the portal system, as well as by purgatives and by ipecacuanha. A relaxed and atonic state is mitigated by sulphuric acid, nux vomica, and tonics generally. Fermentation is checked by creasote, by the hyposulphites and sulphites, by charcoal. But these and other agents that remove the local hindrances of digestion, and facilitate the process, we shall have to notice more particularly.

4. A fourth class of remedies in disease of the stomach of a functional kind are those general agents which act in a secondary manner upon the stomach. They are amongst the most important and powerful remedies that we possess for the alleviation of these maladies. To those in whom the cares and fatigue of an active life have exhausted the strength of the system, and in whom the stomach as part of that system is in an enfeebled state, the invigorating effect of rest and change, of bracing highland and mountain air, of a complete unbending of the mind, and repose from its wonted pursuit, is more effective than merely medicinal treatment. Mental distress and anxiety are effectual barriers to digestion, and far more easy is it to prescribe a medicinal stimulant than to calm the mind and quiet perturbed feelings; and we believe, that the province of the physician extends much farther than the mere thought of the present bodily ailment, if he would restore to