CHAP. II.] 



' PEPSINOGEX.' 



101 



too that whilst glycerin extracts, whether of pyloric or cardiac end, 

 contained pepsin, in 'the latter case the extract was very much 

 more active than in the former, and much freer from mucin. The 

 view was held by many that the pyloric glands had nothing to do 

 with the secretion of the essential constituents of the gastric juice, 

 and that the pepsin which can be extracted by glycerin or by dilute 

 hydrochloric acid was pepsin which had been merely absorbed by the 

 mucous membrane of the pyloric region, though elaborated by the 

 glands at the cardiac end. In the discussion which took place on 

 this interesting question, v. Wittich 1 took a leading part in support 

 of the imbibition-theory of the origin of the pepsin of the pyloric 

 region, whilst Ebstein and Griitzner undertook to prove that pepsin 

 is not merely a product of the activity of the peptic glands proper, 

 but likewise of the pyloric glands 2 . 



Pepsinogen. 



Ebstein and 

 Grutzner's 

 theory of 

 pepsinogenic 

 substance. 



The views of Ebstein and Griitzner were largely 

 founded upon the observation made by them that a 

 a hydrochloric acid extract of a gastric mucous mem- 

 brane digested albumen very much more actively than 

 a glycerin extract of a gastric mucous membrane 

 the two extracts being diluted with hydrochloric acid to an equal 

 extent before being tested. The difference in the digestive power of 

 the two extracts held both in the case of the fundus and of the 

 pyloric region of the stomach. The method of comparing digestive 

 power was that of Griinhagen. On the assumption that glycerin 

 takes out all .the pepsin from the gland-cells, it followed that there 

 was some substance in the mucous membrane which in some way 

 or other under the action of hydrochloric acid gave rise to pepsin. 

 This pepsinogenic substance, as they called it, they considered might 

 be a combination of pepsin with the proteids of the gland-cells, 

 or not completely formed pepsin. The proof however is not a valid 

 one, since glycerin does not extract all the pepsin from proteids; 

 thus, as noticed by Wittich and by Ebstein and Grutzner themselves, 

 if fibrin be placed in a glycerin extract of pepsin, it takes up a 

 portion of pepsin, and this cannot be extracted from it by glycerin ; 

 and the same holds if a neutralized acid extract be taken instead of a 

 glycerin extract. Ebstein and Grutzner came to the conclusion that 

 the pepsinogenic substance was not extracted by glycerin: that it 

 was split up by dilute sodium chloride solution, as well as by hydro- 

 chloric acid, to give rise to pepsin. On both of these points compare 

 below. 



1 v. Wittich, ' Ueber die Pepsinwirkung der Pylorusdriisen.' Pfliiger's Arclnv. Vol. 

 vii. p. 18. 



2 W. Ebstein und P. Griitzner, 'Ueber den Ort der Pepsinbildung im Magen.' 

 Pfliiger's Archiv, Vol. vi. p. 1. 



