468 DIGESTION. 



Besides erepsin and the other enzymes mentioned, the intestinal 

 mucosa also contains antienzymes, antipepsin and antitrypsin (DANILEW- 

 SKY and WEiNLAND 1 ), also enterokinase or a mother-substance of the 

 Fame, and finally also the so-called prosecretin. These two last-men- 

 tioned bodies, which are closely connected with the secretion of pancreatic 

 juice, will be discussed in connection with this digestive fluid. 



The various enzymes are not formed in equal quantities in all parts 

 of the intestine. Diastase and invertase occur, according to BOLDY- 

 REFF, all through the intestine, while the lipase on the contrary occurs 

 only in the lower parts. The kinase occurs only in the upper part of the 

 intestine (BOLDYREFF, BAYLISS and STARLING, DELEZENNF). Accord- 

 ing to HEKMA the kinase occurs in- all parts of the intestine, but most 

 abundantly in the duodenum and the upper part of the jejunum. The 

 enzymes, FALLOISE claims, generally occur in greatest abundance in 

 the upper parts of the intestine; but the erepsin occurs to a greater 

 extent in the jejunum than in the duodenum. According to the investi- 

 gations of VERNON the behavior of erepsin is not the same in different 

 animals. In cats and hedge-hogs the duodenum is richer in erepsin than 

 the jejunum and ileum; in rabbits it is the reverse, namely, the ileum 

 is much richer than the duodenum. The secretin, according to BAY- 

 LISS and STARLING, is formed entirely in the upper part of the intestine. 

 The epithelium-cells of the glands or the mucous membrane are generally 

 considered as the seat of formation of the enzymes, and the same is 

 true also for the enterokinase, according to BAYLISS and STARLING, 

 HEKMA, FALLOISE, and others, which, however, DELEZENNE says, 2 is 

 formed in the leucocytes and PEYER'S glands. 



BOTTAZZI 3 obtained a very complex protein from the intestinal mucosa, 

 which is readily soluble in water and alkali but is precipitated by acids. It 

 coagulates at 55 to 56 and probably also contains carbohydrate and considerable 

 iron. Intravenous injection of this protein brings about an abundant secretion 

 of saliva, pancreatic juice, bile, and intestinal juice, and promotes the peristalic 

 movements of the intestine. 



Erepsin. This enzyme, discovered by O. COHNHEIM, has no direct 

 action upon native proteins with the exception of casein, but has the 

 power of splitting proteoses, peptones and certain polypep tides. In 

 this change mono- as well as diamino-acids are produced. Erepsin 

 occurs in the mucous membrane and in the intestinal juice of man as well 

 as of dogs; the mucous membrane seems to be richer than the juice 



1 See footnote 2, p. 462. 



2 Boldyreff, Arch. d. scienc. biolog. de St. Pe"tersbourg, 11; Bayliss and Starling, 

 Journ. of Physiol., 29, 30; Hekma, 1. c.; Falloise, see Biochem. Centralbl., 4, p. 153; 



Vernon, Journ. of Physiol. ,-33; Delezenne, Compt. rend. soc. biolog., 54 and 56. 



3 See Biochem. Centralbl., 3. p. 65. 



