108 PHYSIOLOGY. 



is changed into urea in the liver by a ferment, arginase. Drechsel 

 has estimated that about one-ninth of the urea excreted could arise 

 from this source alone. 



(a) Other diamino acids: Diamino-glutaric acid, diamino- 

 adipic acid. 



3. HYDROX-AMINO ACIDS. Serin, tyrosin, found also in elder- 

 berries, in potatoes and germinating cucumbers. 



Tyrosin (C^^NOs) belongs to the aromatic group, and is 

 known as oxyphenyl-amido-propionic acid. It is a constant associate 

 of leucin. It is from tyrosin, however, that cresol and phenol are 

 formed. 



4. A-PYRROLIDINCARBOXYLIC ACID, or prolin. 



5. CASEANIC ACID. Caseinic acid. 



6. TRYPTOPHANE OR INDOL-AMINO-PROPIONIC ACID. This crys- 

 talline body gives, on distillation, indol and skatol. When the ami do 

 bodies are formed from the proteid molecule by the trypsin, a nucleus 

 of the proteid molecule remains, which is a polypeptid. 



7. THE SULPHUR BODIES. Albumin, when treated with lead 

 salts in the presence of caustic alkali, yields a black coloration, indi- 

 cating the presence of sulphur in the molecule. One of these bodies 

 is cystin. 



8. THE CARBOHYDRATE GROUP. There are certain proteids. 

 amongst which are mucins and cartilage, which readily yield 

 a carbohydrate group on hydrolysis. Serum-albumin and egg-albu- 

 min contain a carbohydrate group which forms no small part of the 

 whole molecule of albumin. Thus egg-albumin contains glycosamin 

 this last fact is important in the consideration of diabetes; the sugar 

 comes from the proteid. 



Glycosamin injected into the circulation is in great part elimi- 

 nated as such. Proteids containing glycosamin are completely oxi- 

 dized. One-twelfth of egg-albumin is glycosamin. 



It has been shown by Giselt that alcohol, when given either by 

 the stomach or rectum, increases the secretion of the pancreatic juice 

 by an action through the vagi. The vagi contain the secretory nerves 

 of the pancreas. However, alcohol reduces the digestive activity of 

 the trypsin, the amylopsin, and the steapsin. 



I have found that an infusion of the pancreas, when injected per 

 jugular, decreases the pulse and the arterial tension; afterward the 

 tension rises. 





