( 257 ) 



Both tables show that after 36 hours more pepsin and also more 

 pepsinogen had passed into the agar than after 18 hours. 



Further a comparison of tables TV and V makes it evident that 

 the digestion of albumen in experiments made with neutral agar, 

 is more considerable than where alkalic agar has been employed. 

 This result may also tend (o confirm the reliability of the method; 

 for into the neutral agar pepsin and pepsinogen may enter, the 

 latter of which under the influence of hydrochloric acid produces 

 pepsin, whilst in the alkalic agar oidy pepsinogen is found. And as 

 we have seen invariably in all our experiments, the quantity of 

 enzyme and pro-enzyme at identical spots of the (wo symmetrical 

 parts of the stomach turns out to be the same. 



I wish to observe here that the digestion of serum-albumen takes 

 place much more quickly than that of the egg-albumen used. Giassner 

 was the first to point out the advantage of coagulated serum, and I 

 may confirm it from my own experience. Serum albumen lias 

 moreover the advantage that without preparation such as cuffing 

 up and filtrating, it can be used after simply being coagulated in 

 glass tubes. 



Owing to accidental circumstances no serum-albumen has been 

 used for the experiments described in this paper. 



4. Distribution of rennet-ferment. 



To demonstrate the presence of rennet-ferment and to know its 

 distribution in the gastric mucous membrane, about (he same method 

 was applied as that used for the investigations relating to pepsin 

 and pepsinogen. Only the agar-columns had a greater diameter than 

 in the pepsin experiments, viz. 35 instead of 22 mM. The contents 

 accordingly were 5 cc. instead of 3 cc. Moreover it was self-evident 

 that the quantitative determination of the rennet-ferment had to be 

 effected in another way. The columns having been on the mucous 

 membrane for some hours, the agar was cut fine and mixed in a 

 test-tube with l /, cc. HOI 0.4% and afterwards with 10 cc. of milk. 

 Then the test tube was plunged into a bath of water at 37.5°, after 

 which it was noted down every half minute where coagulation had 

 taken place. 



The presence of some hydro-chloric, acid did not impair the expe- 

 riment. Previous tests had shown that in a mixture of 5 cc. neutral 

 agar '/, cc. HOI of 0.4% and 10 cc. of milk coagulation did not 

 set in till more than an hour after. As the following series of expe- 

 riments demonstrates the addition of only '/, cc. of HOI can hardly 



17 



Proceedings Royal Acad. Amsterdam. Vol X 



