Research into the chemical processes in the small intestine of man / by Allan Macfadyen, M.D. Ed., M. Nencki, M.D., and N. Sieber, M.D.

  • Macfayden, Allan, 1860-1907
Date:
[1891?]
Catalogue details

Licence: Public Domain Mark

Credit: Research into the chemical processes in the small intestine of man / by Allan Macfadyen, M.D. Ed., M. Nencki, M.D., and N. Sieber, M.D. Source: Wellcome Collection.

    13/44 (page 399)
    that the alkaline reaction of the colon’s mucosa was always more intense than that of the ileums. The statement found in most handbooks that the chyme is already neutralised in the upper part of the small intestine, and generally reacts alkaline in the lower part, is not correct. The alkaline reaction first begins in the large intestine, after the food has passed through the ileo-caecal valve. Through the continuous neutralisation of the chyme on the alkaline mucous coat of the small intestine a precipitate results. This precipitate consists of mucin, bile acids, fat, cholesterin, and a neutralisation precipitate of albumen. This precipitate adheres to the mucous coat, and this circumstance may well be of importance for the absorption of fats. When we mixed the filtered discharge from the fistula with a 5 per cent, solution of glycocholate of soda, a precipitate did not immediately occur; but after half an hour all the glyco- cholic acid was precipitated. The fact that the food-mass in the entire length of the small intestine has an acid reaction, and that, consequently, the pan¬ creatic digestion of proteids, carbohydrates, and fats takes place in an acid medium, should be taken into account in future artificial digestion experiments. It has been already shown by one of us1 that by acid reaction the pancreas splits into their components, fats and acid ethers or “ esters.” Experiments, to be immediately described, show further, that the acid reaction of the food-mass has a distinctly inimical influence on those bacteria which only flourish in neutral or alkaline nutrient media. It was of especial interest to discover the share the numerous bacteria present in the small intestine take in the decomposition of the food. The acid reaction of the food-mass and its faintly and not always putrefactive odour, were already against the supposition of any active decomposition by their agency. Still it was possible that, whilst on account of deficient oxygen the final products of putrefaction—such as indol, skatol, phenol, volatile fatty acids, &c.—would not be found, the first decom¬ position products of the proteids (the amido acids) might be present.2 1 Archivfiir. Exper. Pathol, u. Pharmakol., vol. xx. p. 375, 1885. 2 Wiener Akad. Berichte, 1889.