. A text-book of human physiology . thirteen minutes, which continued for about three hours. Neither egg albuminnor albumose nor bread had any such effect. It appears therefore that certainextractives contained in meat, to which however creatin and creatinin do notbelong, certain constituents of milk, etc., are specific stimuli for the , there are experiments which show that once the secretion is startedby these substances, it is considerably augmented when, for example, egg albu-min, of itself but slightly active, is introduced. In the same way starch intro-duced with meat
. A text-book of human physiology . thirteen minutes, which continued for about three hours. Neither egg albuminnor albumose nor bread had any such effect. It appears therefore that certainextractives contained in meat, to which however creatin and creatinin do notbelong, certain constituents of milk, etc., are specific stimuli for the , there are experiments which show that once the secretion is startedby these substances, it is considerably augmented when, for example, egg albu-min, of itself but slightly active, is introduced. In the same way starch intro-duced with meat can intensify the secretory process considerably. THE GLANDS OF THE STOMACH 265 From these observations we can form provisionally the following concep-tion of the conditions for secretion in the stomach. Secretion of gastric juiceis started by a complicated reflex process, which is set in operation by thesight of food as well as by its passage through the mouth and oesophagus, and Hours 12 3 4 3 4 5 0 8 y 10 1 2 3 4 5 6 mmBSSSSSSSS. Mt-at. Bread. Milk. Fig. 103.—Hourly course of secretion of gastric juice in the dogs stomach, after Pawlow. Ex-clusive diets of meat, bread, and milk were given. is mediated by the vagus. This secretion itself lasts for a fairly long time;but it is augmented by the stimulating influence on the mucous membrane ofingested water and. al)ove all, of certain extractives, contained in the food. Chigins experiments on the course of the secretion in the blind sac withthe vagi preserved show very instructively how the activity of the mucous mem-brane under the influence of the vagus reflexes and the excitation of the food,is adapted to the momentary requirements upon it. With all the articles offood thus far tested the secretion began at about the same time. It reached itsmaximum during the first or the second hour (with milk during the third hour).After the maximum was reached the secretion fell immediately and becamegradually less and less until i
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