DIGESTION. 



ence of gelatine), besides gelatin peptone NENCKI obtained leucin, 

 glycocoll, ammonia, a base, C 8 H U N, and other products. The pure 

 enzyme, according to KUHITE, gives neither glycocoll nor leucin 

 with gelatin. The gelatin-giving substance of the connective tis- 

 sues is not directly dissolved by trypsin, but only after it has been 

 treated with acid or after soaking in water at -}- 70 C. By the 

 action of trypsin on hyalin cartilage the cells dissolve, leaving the 

 nucleus. The basis is softened and shows an indistinctly-con- 

 structed network of collagenous substance (Kunins and EWALD). 

 The elastic substance, the structureless membrane, and the mem- 

 brane of the fat-cells are also dissolved. Parenchymatous organs, 

 such as the liver and the muscles, are dissolved to the nucleus, and 

 also connective tissue, fat-corpuscles, and the remainder of the 

 nervous tissue. If the muscles are boiled, then the connective tissue 

 is also dissolved. Trypsin seems to be without action on chitin 

 and horny substance. Oxyhcemoglobin is decomposed by trypsin 

 with the splitting off of haematin. Hcemoglobin, on the contrary, 

 wh6n the access of oxygen is completely prevented, is not decom- 

 posed by trypsin (HoppE-SEYLEE). Trypsin does not act on fats 

 or carbohydrates. 



It was already brought out above that trypsin does not exist 

 ready formed in the gland, but more likely, as HEIDENHAIN has 

 shown, the gland contains a corresponding zymogen. The maxi- 

 mum quantity of such zymogen in the gland occurs 14-16-18 hours 

 after an abundant meal, and the minimum 6-10 hours after. 

 This zymogen is not changed by glycerin so that it forms trypsin, 

 but is easily changed by water and acids. A soda solution of 1-1.50, 

 on the contrary, prevents almost entirely the changing of the 

 zymogen. If we allow the gland to lie in the air it gradually 

 becomes acid, and this leads to the formation of an enzyme in which 

 the oxygen seems to be active, as is usual in the conversion of the 

 zymogen into trypsin. It is very probable also that the two other 

 enzymes are formed from corresponding zymogens, and this has 

 been shown to be plausible in regard to the diastatic enzymes by 

 LIVERSIDGE. 



After a plentiful meal HEIDENHAIN found in dogs in the first 

 stages of digestion, when the secretion of pancreatic juice was 

 most active, that the glandular cells became smaller owing to the 



