: Les Explorateurs du Centre de l'Afrique by Durand L Abb Durand Douard Joseph - Africa Central Discovery and exploration FR Histoire

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Stomach digestion consists mainly in the action of pepsin upon proteids in the presence of hydrochloric acid and in the curdling of milk by rennin.

Pepsin and rennin are secreted by the gastric glands as zymogens--pepsinogen and renninogen, respectively--which are converted into pepsin and rennin by hydrochloric acid. Hydrochloric acid is secreted by certain cells of the fundus glands. It at once combines loosely with the proteids of the food, forming acid-albumin, the first step in proteid digestion. Hydrochloric acid, which is thus loosely combined with proteids, is called "combined" hydrochloric acid. The acid which is secreted after the proteids present have all been converted into acid-albumin remains as "free" hydrochloric acid, and, together with pepsin, continues the process of digestion.

At the height of digestion the stomach-contents consist essentially of: Water; free hydrochloric acid; combined hydrochloric acid; pepsin; rennin; mineral salts, chiefly acid phosphates, of no clinical importance; particles of undigested and partly digested food; various products of digestion in solution. In pathologic conditions there may be present, in addition, various microscopic structures and certain organic acids, of which lactic acid is most important.

A routine examination is conveniently carried out in the following order:

Give the patient a test-meal upon an empty stomach, washing the stomach previously if necessary.

At the height of digestion, usually in one hour, remove the contents of the stomach with a stomach-tube.

Measure and examine macroscopically.

Filter. A suction filter is desirable, and may be necessary when much mucus is present.

During filtration, examine microscopically and make qualitative tests for-- free acids; free hydrochloric acid; lactic acid.

When sufficient filtrate is obtained, make quantitative estimations of-- total acidity; free hydrochloric acid; combined hydrochloric acid .

Make whatever additional tests seem desirable, as for blood, pepsin, or rennin.

A. OBTAINING THE Gastric juice is secreted continuously, but quantities sufficiently large for examination are not usually obtainable from the fasting stomach. In clinical work, therefore, it is desirable to stimulate secretion with food--which is the natural and most efficient stimulus--before attempting to collect the gastric fluid. Different foods stimulate secretion to different degrees; hence for the sake of uniform results certain standard "test-meals" have been adopted. Those mentioned here give practically the same results.

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