EREPSIN. PANCREAS. 469 



(SALASKIX, KUTSCHER and SEEMANN 1 ). An enzyme like erepsin also 

 occurs in the pancreas (BAYLISS and STARLING, VERNON), and this has 

 the power of acting upon casein, but not, or only faintly, upon fresh fibrin. 

 This erepsin is probably identical with the enzyme nuclease, discovered 

 by F. SACHS in the pancreas, which acts upon nucleic acids, while 

 KAKAYAMA claims that erepsin differs from trypsin in having a cleavage 

 action upon nucleic acids. Erepsin shows a great similarity to the 

 intracellular enzymes active in autolysis, and according to VERNON, 

 erepsins occur in the various tissues of invertebrates as well as vertebrates. 

 These tissue erepsins, which are closely related to the autolytic enzymes, 

 if they are not identical with them, behave somewhat differently from the 

 intestinal erepsin and are not identical therewith. Enzymes, haxing 

 an action similar to erepsin, occur, VINES believes, 2 in all plants so far 

 investigated. 



Erepsin becomes inactive on heating to 59. It works best in alkaline 

 solution, but has hardly any action in faint acid reaction. In this 

 regard, as well as by the fact that only a little ammonia is split off by its 

 action upon peptone substances, it differentiates itself from certain of 

 the autolytic enzymes studied so far. The optimum of alkalinity is, accord- 

 ing to EuLER, 3 at least in the splitting of a polypeptide, much lower 

 than the optimum for tryptic digestion. 



The secretion of the glands in the large intestine seems to consist 

 chiefly of mucus. Fistulas have also been introduced into these parts 

 of the intestine, which are chiefly, if not entirely, to be considered as 

 absorption organs. The investigations on the action of this secretion 

 on nutritive bodies have not as yet yielded any positive results. 



IV. THE PANCREAS AND PANCREATIC JUICE. 



In invertebrates, which have no pepsin digestion and which also have 

 no formation of bile, the pancreas, or at least an analogous organ, seems 

 to be the essential digestive gland. On the contrary, an anatomically 

 characteristic pancreas is absent in certain vertebrates and in certain 

 fishes. Those functions which should be regulated by this organ seem 

 to be performed in these animals by the liver, which may be rightly 

 called the HEPATOPANCREAS. In man and in most vertebrates the for- 

 mation of bile, and of certain secretions, containing enzymes important 

 for digestion, is divided between the two organs, the liver and the pancreas. 



* Cohnheim, Zeitschr. f. physiol. Chem., 33, 35, 36, and 47; Salaskin, ibid., 35; 

 Kutscher and Seemann, ibid., 35. 



2 Bayliss and Starling, Journ. of Physiol., 30; Vernon, ibid., 30 and 33; F. Sachs, 

 Zeitschr. f. physiol. Chem., 46; Nakayama, ibid., 41; Vines, Annals of Botany, 18, 

 19. and 23 



'Zeitschr. f. physiol. Chem., 51. 



