These are the three forms of matter through which the fermentative agency, referred to in the preceding general observations, is remedially exercised. I shall consider each of them separately.

I. Gastric Juice. This is collected from the stomachs of fasting animals, as the sheep, calf, and pig, and is prepared for use by filtering. it is a limpid, light-yellowish, or brownish-yellow liquid, of a peculiar soup-like odour and saltish taste, heavier than water, and of an acid reaction. At a temperature of 100° or less, it dissolves nitrogenous food, and converts glucose into lactic acid; but loses this property at the boiling point. its solvent power is impaired by the neutralization of its acid, by a heat of 122° or more, and by strong alcohol. The juice is supposed to owe the property to a peculiar principle called pepsin, which has been isolated, though perhaps not in a pure state. When the solvent power is lost by the removal of the acid, it is restored by adding either lactic or muriatic acid to the liquid. Excluded from the air, gastric juice will keep unchanged for a long time; but, upon exposure, it is soon decomposed and loses its digestive power.

The gastric juice itself is seldom if ever used internally. The late Dr. Physick, of Philadelphia, employed it with much advantage in carious and sloughing ulcers, to dissolve the dead bone and flesh. it thus not only removed foul and irritating matters, and gave a clean surface to the ulcer, but seemed to promote the healing process by a gentle stimulation.

In the Boston Medical and Surgical Journal for April, 1856 (liv. 212), the cases of two persons are recorded by Dr. P. W. Ellsworth, of Hartford, Connecticut, in whom pieces of flesh, lodged in the oesophagus, and irremovable by the forceps or probang, were so far dissolved or softened by the use of gastric juice, that they were swallowed by the natural action of the parts. The gastric juice employed was taken from the stomach of a pig, and given in the dose of a teaspoonful in one case, and half that quantity in the other, repeated about once an hour.

II. Rennet. Rennet is an infusion of the dried stomach of the calf in water or wine. The stomachs of other animals would probably answer the same purpose. The characteristic property of rennet, for which it has been long used, is that of coagulating milk; and it ought to be of such strength, that a teaspoonful of it will coagulate a pint of milk in five minutes. (Ed. Month. Journ., Jan. 1853, p. 31.) it should be used as fresh as possible; as it is liable to decomposition upon keeping. Besides this coagulating power, it has been found to have the property of converting glucose or sugar of grapes into lactic acid; and probably, aided by this acid or the muriatic, it would exercise the digestive power of the gastric juice over nitrogenous articles of food. it appears to have been long popularly employed, in some parts of England, to aid digestion. (Med. Times and Gaz., April, 1857, p. 411.) Dr. David Nelson, of Birmingham, used this remedy or its equivalent, under the name of liquor pepticus, so early as 1851, in various diseases connected with deficient digestive power, as a substitute for the gastric juice. (Lancet, Am. ed., Nov. 1858, p. 362.) in 1853, Dr. James Gray, of Glasgow, published in the Edinburgh Monthly Journal of Medical Science (Jan. 1853, p. 31) a paper in which he strongly recommends rennet in diabetes, having employed it advantageously in that disease, with the view of changing into lactic acid the glucose which might be generated from starch in the primae viae, and thus preventing its entrance into the circulation. Other testimony has since been given to the favourable influence of rennet in diabetes, though it has often also failed entirely. it might be used, with reasonable hope of benefit, in all cases of imperfect digestion, dependent on deficiency of gastric juice. The dose is a teaspoonful three times a day, to be given immediately before, or immediately after each meal.*

III. Pepsine. - Pepsinum. The discovery of a peculiar fermentative principle in the gastric juice naturally led to attempts to isolate it for medical use; and, though complete success has not attended these efforts, yet the experiments have resulted in the preparation of a substance, representing, in a concentrated state, the virtues of the gastric juice, and convenient for administration. This substance has been called pepsine; but the reader must understand that, by the term, as thus used, is not meant the pure proximate principle, to which the name was first chemically applied. it only contains that principle in a convenient form for use. The original preparation was due to the joint labours of Dr. L. Corvisart and M. Boudault, of Paris, the latter having performed the part of the pharmaceutist in the work. (Lancet, Oct. 1858, p. 260.) it is made from the stomachs of sheep, by scraping off the mucous membrane, digesting it in water, precipitating the infusion with acetate of lead, decomposing the compound of pepsin and oxide of lead thus obtained by sulphuretted hydrogen, filtering the liquid containing the pepsin, and evaporating to a syrupy consistence. Sufficient starch is then added to form a dry powder, which is the preparation in question. For the precise mode of proceeding, the reader is referred to the U. S. Dispensatory (12th ed., p. 1591).

* Rennet Wine. Dr. Geo. Ellis prepares this in the following manner. Taking the stomach, or rennet-bag, of a calf just killed, and cutting off about three inches of the cardiac extremity, which contains few of the secreting follicles, he slits the remainder longitudinally, wipes it gently with a dry napkin, but so as to remove as little as possible of the clean mucus, then cuts it into small pieces (the smaller the better), puts the whole into a common wine-bottle, and fills the bottle with good sherry wine. The bottle should be well corked, and remain so for three weeks, at the end of which time it is fit for use. The dose is a teaspoonful, in a wineglassful of water, immediately after meals One teaspoonful, at 100° F., will coagulate, in one or two minutes, about eight ounces of milk. (Am. Journ. of Med. Sci., Oct. 1862, p. 510; from the Dub. Med. Press, July 16, 1862.) - Note to the third edition.

Properties

The genuine pepsine of Boudault, when dissolved in water, is precipitated by tannic acid, acetate of lead, and strong alcohol; and 15 grains of it should, at a temperature of 100°, and with the aid of a little lactic or muriatic acid, cause 90 grains of boiled and comminuted white of egg or chopped meat, to be dissolved by half a fluidounce of water.

Medical Effects and Uses

Dr. Corvisart first suggested the use of this preparation, and employed it practically as a remedy. it is obviously indicated in all cases in which either the stomach or the system at large is suffering from imperfect digestion, owing to deficiency either in the quality or quantity of the gastric juice. it must be clearly understood that it is a temporary remedy, and that the use of it should not supersede measures for the permanent restoration of the healthy function of the stomach when this is practicable. it is an excellent palliative in dyspepsia; often obviating for a time the flatulence, excessive acidity, eructations, pains and distressing sensations, whether in the stomach or by sympathy elsewhere, and various disturbance of function, which so frequently attend that complaint. Nausea and vomiting are sometimes corrected by it; and it has relieved the vomiting of pregnancy after all other means had failed. The appetite is not unfrequently restored after having been entirely lost; and the general system, debilitated by the want of a due supply of nourishment, is invigorated and in all respects improved. Hence the remedy has proved useful in scrofula, phthisis, cancerous affections, and others dependent on or associated with a defective or depraved nutrition. it may very properly be tried in all cachectic diseases in which digestion is in fault, and among others in diabetes.

Administration

The dose is fifteen grains, to be taken three times a day, immediately before each meal. it may be administered in powder, or suspended in syrup, or in a cupful of soup. A wine has been recommended prepared by mixing two drachms of pepsine, a fluidounce of distilled water, two fluidounces of white wine, three fluidrachms of officinal alcohol, and an ounce of sugar, allowing the mixture to stand till solution takes place, and then filtering. A tablespoonful of this, containing about fifteen grains of the pepsine, may be given for a dose, and repeated as above. A few drops of lactic or muriatic acid should be added to each dose, when there is reason to think that there may be deficiency of acid in the stomach.