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.

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    Nature without bacterial life.” But, on the other hand, Pas¬ teur’s preconceived opinion, as stated above, is most likely an erroneous one, at least as regards vertebrate animals. We have seen that, when the acid chyme passes from the stomach into the intestine, it becomes neither neutral nor alkaline, but preserves its acid reaction down to the ileocoecal valve. As a result of the acid reaction, a decomposition of proteids by bacteria does not take place, or at most inconstantly and to a hardly perceptible degree. And not only that, the action of the pancreatic juice on proteids is weakened by the acid reaction of the intestinal contents. The products so easily obtained outside the body by the action of trypsin on proteids (leucin and tyrosin) were not to be found in the small intestine. Further, the decomposition of the food-mass by bacteria is con¬ fined to the carbohydrates. The products formed by the bacteria from sugar are—the two lactic acids, acetic acid, succinic acid, ethyl alcohol, carbonic acid, and hydrogen. The ash analyses we made prove that an important function of the small mucosa of the intestine is to supply constantly alkaline carbonates for the purpose of neutralising the acids produced by the fermentation of the sugar. No one can suppose that these fermentation products are necessary for the maintenance of our life. It is much more to be regarded as a loss that a portion of the dextrose formed by the pancreatic enzyme out of starch is not absorbed, but serves as nutriment for the parasitic bacteria of the digestive tract. It will be unwelcome news for some that a considerable amount of alcohol is produced in our bodies, not only in the small, but also in the large intestine, in the latter by the bac¬ terium coli commune. The possible decomposition of the fats by the bacteria does not need to be considered here. It has already been shown by one of us1 that the presence of bacteria does not materially affect the disintegration of fat in the intestine. The excellent researches of Immanuel Munk 2 have proved that about 90 per cent, of the food fats are absorbed as neutral fats, and that free fatty acids are already transformed into neutral fats in the walls of the intestine. 1 Archivf. Exper. Pathol, u. Pharm., vol. xx. p. 374. 2 Virchow's Archiv, vol. xxv. pp. 407-467.