Diseases of the intestines and peritoneum / by Hermann Nothnagel ; edited, with additions by Humphrey D. Rolleston ; authorized translation from the German, under the editorial supervision of Alfred Stengel.
- Hermann Nothnagel
- Date:
- 1904
Licence: Public Domain Mark
Credit: Diseases of the intestines and peritoneum / by Hermann Nothnagel ; edited, with additions by Humphrey D. Rolleston ; authorized translation from the German, under the editorial supervision of Alfred Stengel. Source: Wellcome Collection.
Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.
28/1106 page 20
![that there is an insohi])le prozymogen in the pancreatic tissue which yields definite amounts of soluble trypsin-zymogen and of soluble rennetic zymogen ; and that there is also an insoluble diastatic pro- zymogen which yields soluble diastatic zymogen.—Ed.] This enzyme acts on proteids in alkaline or neutral medium. A markedly acid reaction inhibits, while slight degrees of acidity seem to favor, tryptic digestion; hence proteolysis occurs more rapidly in the presence of small quantities of acetic or lactic acid than in a neutral medium (Lindenberger). Albumin becomes dissolved without swelling ; all the proteids—with the exception of serum-albumin (Neumeister) —are first converted into a globvdin which is insoluble in water, and are later converted into peptones soluble in water. According to Kiihne, tryptic digestion occurs as follows: The proteid molecule, after passing through numerous intermediate stages, is converted into two different peptones—called hemipeptone and antipeptone. Anti- peptone resists any further catabolic change during digestion, while hemipeptone is converted into leucin, tyrosin, and asparaginic acid. This scheme of tryptic digestion is not universally accepted; we do know, however, that large quantities of tyrosin and leucin are always formed (Kiihne). To take an example, 382 grams of desiccated fibrin were digested artificially with pancreatic juice, and after six hours 343.7 grams were found to be dissolved; the products formed consisted of 212.2 grams of peptone, 13.3 grams of tyrosin, and 31.6 grams of leucin. Schmidt-Miihlheim and Hofmeister found only small quan- tities of leucin and traces of tyrosin in the intestinal tract of dogs and pigs. Sheridan Lea found larger quantities in dogs; thus the intestinal contents of a dog six hours after a meal of 500 grams of meat contained 1 gram of leucin and 0.3 gram of tyrosin. Indol is not a product of pancreatic digestion, as was formerly be- lieved, but owes its origin to the action of micro-organisms on proteids. In addition to small quantities of ammonia (Hirschler, Stadelmann) another unknown substance is found in the intestine, when putre- factive processes are inhibited. It gives a violet color when treated ■with chlorin or bromin water, and may be considered as a chromogen. This substance was also described by Tiedemann and Gmelin, and was later designated as proteinochrome or tryptophane. Since it is con- stantly formed during advanced proteolysis,—that is, when the proteid molecule undergoes very thorough decomposition,—this chromogen is particularly interesting. Of the organic bases (hexabases), there are formed lysin (Drechsel and Hedin), some histidin, and a large amount of arginin (Kutscher), In tryptic digestion of globin leucinimid has been demonstrated (Sal- askin), and cystin in the tryptic digestion of blood-albumin (Morner). The action of trypsin on other bodies is as follows : The proteids undergo cleavage, and the albuminoids thus split off undergo farther digestion. Casein is converted into proto- and deuterocaseoses and casein-peptone (Chittenden). Gelatin is first converted into proto- and deuterogelatose, then into a peptone, and finally into amido-acids. The](https://iiif.wellcomecollection.org/image/b21170010_0028.jp2/full/800%2C/0/default.jpg)
