This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Hypersecretion of gastric juice is determined by withdrawing the contents of the stomach in the morning after lavage the previous evening. If more than fifty cubic centimetres are obtained, hypersecretion may be said to exist, the exact nature of which is to be determined by the Giinzberg test (p. 525). Suggestions for the diet of such cases are given on p. 534. Gastric atony is determined by finding in the morning washing of the stomach undigested particles of food eaten the night before.
The microscopic examination of the washing will exhibit bacteria, sarcinae, and saccharomyces. The treatment of this condition is given under Chronic Gastric Catarrh (p. 540) and Dilatation of the Stomach (p. 546).
The presence of pepsin may be determined by digesting either egg albumin or blood fibrin, the latter being preferred. The fibrin is whipped from fresh beef blood and washed in water until it becomes white. A small piece is placed in a test tube with fifteen or twenty cubic centimetres of filtered gastric juice, and kept at a uniform temperature of 400 C. for two or three hours. If there is but little normal HC1 present, a few drops more should be added. If no digestion occurs after some hours, pepsin is absent and the fibrin will decompose. Quantitative or comparative tests may be made by using definite amounts of fibrin and gastric juice, and noting the time required for complete digestion.
The presence of the rennet ferment is easily demonstrated by adding a few cubic centimetres of the filtered gastric juice to a half-teacupful of fresh milk, and keeping the mixture for a short time at 400 C. A loose coagulum forms with a limpid yellowish whey if rennet be present.