200 



Scientific Proceedings (121). 



The activated adsorbents were extracted with baryta and 

 glacial acetic acid respectively, and the influence of these ex- 

 tracts were tested on the growth of yeast cells and streptococci. 

 The results which we obtained and which are embodied in Tables 

 I and II, show that the substances which stimulate the growth of 

 streptococci and yeast cells, as extracted from beef-heart and 

 autolyzed yeast solutions, apparently belong to the class of 

 vitamines of the water-soluble B type, but are not identical with 

 B vitamine. They are comparable in activity and show similar 

 properties in that they are easily extracted from their natural 

 sources by the same adsorbents, and are again recovered from the 

 adsorbents without appreciable loss in activity. 



Action of Protein Hydrolysates on Bacteria and Yeast 



Cells. 



It is very well known that protein hydrolysates stimulate the 

 growth of certain bacteria, and this stimulating action has been 

 attributed at various times to the presence of unknown substances 

 in the protein molecule. To test out this theory, we subjected 

 to acid hydrolysis twelve animal and ten vegetable proteins, which 

 were prepared and purified by the usual methods, particular care 



table III. 



Quantitative Action of Protein Hydrolysates on Streptococci. 

 p H . of Standard Culture Medium = 7.3. 



No. 



Hydrolysates of the Proteins. 



Growth. 



Change 



(1 c.c. used in each test.) 



in p H . 



1. 





+ 



5-8 



i(a). 







7-3 



2. 



Casein (purified) H2SO4 hydrolysate 



+ 



5-3 



2(a). 







7.0 



3- 





+ 



5-8 



3(a). 







7-3 



4- 





+ 



6.0 



4(a). 







7.2 



5- 



Gelatin (prepared and purified in laboratory) 





7.2 



5(a). 







7-3 



6. 





+ 



6-5 



6(a). 







7-3 



7- 





+ 



4.9 



7(a). 







73 



Note. — Hydrolysates of 18 other proteins found to be inactive. 



