On the digestive ferments and the preparation and use of artificially digested food : being the Lumleian Lectures for the year 1880. Delivered before the Royal College of Physicians / by Wm. Roberts.

  • William Roberts
Date:
1881
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Licence: Public Domain Mark

Credit: On the digestive ferments and the preparation and use of artificially digested food : being the Lumleian Lectures for the year 1880. Delivered before the Royal College of Physicians / by Wm. Roberts. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    slow and imperfect—but its action on liquid casein, as it exists in milk, is marked by a rapidity and completeness of which there is no parallel example in the case of pepsin.] Peptogeyis. I may here advert to a singular view advanced by SchifF in regard to the production and secretion of pepsin and trypsin. Schiff found that when an insoluble aliment such as white-of- egg (or fibrin, or meat which had been deprived of its soluble portions) was introduced into the stomach of a fasting animal no pepsin was secreted, and the albumen remained undigested; but if with the albumen certain soluble aliments were intro- duced into the stomach, then pepsin was produced, and digestion immediately began. To these substances, which had the power of provoking the for- mation and secretion of pepsin, SchifF gave the name oi'pei:)togens. Among the most effective peptogens were found to be solutions of dextrine, extract of meat (or soup), infusion of green peas, bread (which contains dextrine), gelatin, and peptones. On the other hand solutions of grape-sugar, soluble starch, fat-emidsion or gum had no peptogenic effect; and milk and coffee had not much. Schiff further found that peptogenic substances were just as effective when they were injected into the blood, or into the cellular tissue, or introduced as enemata into the rectum, as when they were introduced directly into the stomach. On the other hand when peptogens were injected into the small intestine their influence was not observed—their effect seemed to be annulled by some action of the mesentric glands, or by some change induced in them in their passage along the throracic duct. On the ground of these experiments—and they were nume- rous and oft repeated, and gave constant and decisive results— he concluded that the absorption into the blood of these soluble aliments was a necessary preliminary of proteid diges- tion—that no pepsin or tiypsin was secreted unless these substances existed beforehand in the blood. The first act, according to Schiff, of gastric digestion w^as the absorption from the constituents of a meal of these soluble peptogens by the veins of the stomach. On this followed immediately the secre- tion of pepsin and the commencement of digestion proper.* * See Lpr.ons sur la Phyinolofjie de la Diffestion^Varin, 1867. T. II., p. 200 et seq.— where the experimental evidence on which he relies in set forth at length.
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