( 26J ) 



The action of erepsin consists as we know in its power to change 

 hemialbumose and peptone into products not giving the biuret-reaction. 



Vernon ') has based on this a colorimetric method, to determine 

 the degree of conversion brought about by erepsin and Falloise *) 

 among others, has successfully used it. We too have applied this 

 method, in a somewhat modified form, however. It chiefly consisted 

 in a solution of CuS0 4 being mixed with a NaOH solution. The fluid 

 thus obtained imparts a violet-red colour to peptone. The more the 

 peptone solution from which we started is converted by erepsin, the 

 fainter the violet-red colour will be. It was now investigated, with 

 how much water the standard liquid had to he diluted to produce 

 the violet-red colour observed. 



One of our experiments gave the following result. 



In the peptone-solution (Witte) on which the duodenal-extract 

 has acted, are 46.2% of the original quantity of peptone left. In 

 the peptone-solution acted upon during the same time by the jejunum- 

 agar-extract are still 16% of the original quality of peptone left, 

 and lastly where the ileum-agar-ex tract acted during the same time, 

 14% of the original amount. 



It follows from this that in jejunum and ileum (here was more 

 repsin present than in duodenum, which corroborates so far Falloise's 

 results inasmuch as we too found much more erepsin in jejunum 

 than in duodenum. In the ileum, however, the amount of erepsin is 

 much greater than in the duodenum; Falloise, indeed, notes a diffe- 

 rence in the same direction, but it is only slight. It must be kept 

 in mind though, that our experiments relate to the pig, Falloise's 

 to the dog. 



I may add that in Peyer's plaques hardly any erepsin or entero- 

 kinase was found. 



A number of experiments, made for the researches described above, 

 have been carried out by Mr. R. A. B. Oosterhtis, Med. cand., 

 assistant at the physiological laboratory. 



Conclusion. 



The abo\e researches have shown: 



1. That when agar columns are placed upon the mucous mem- 

 brane of stomach and intestines, enzymes and pro-enzymes are 



*) Vernon. Journal of Physiology. 30, 1903, p. 330. 



2 ) Falloise. Archives internat, de Physiol. 2, 1903/4, p. 299. 



