18 NUTRITION FACTORS IN YEAST AND BACTERIA 



claimed stimulated the growth of bacteria and yeast, but he also 

 found the finally purified substance to be inactive. 



In a previous communication 5 we have shown that we can 

 obtain from beef and beef-heart infusions, peptone and autolyzed 

 brewer's yeast, by adsorption with fullers earth and norit char- 

 coal, certain substances which show a strong growth-stimulating 

 activity on yeast cells and hemolytic streptococci. We have also 

 shown that these substances can be extracted from their com- 

 bination with fullers earth and charcoal by treating these ad- 

 sorbents with baryta and glacial acetic acid respectively. The 

 properties of these substances were found to be similar to those 

 of the vitamine D described by Funk and Dubin 6 . 



In the following work, the authors have tried to show the 

 relationship between the substances found in proteins, and vita- 

 mine D; and that these substances are not present in purified 

 proteins in general but are found associated only with certain 

 proteins. 



EXPERIMENTAL PROCEDURE. 



For this work we have prepared a series of well known pro- 

 teins, consisting of twelve animal and ten vegetable proteins. 

 The proteins of animal origin varied to a great extent, and in- 

 cluded the milk proteins, casein and lactalbumin, three ox-blood 

 proteins, three egg proteins, muscle protein, liver albumin and 

 globulin, and gelatin. 



For the proteins of vegetable origin, we have prepared 

 edestin (from hemp seed) , the wheat and corn proteins, the three 

 proteins from the pea, oryzenin (from rice), hordein (from 

 barley) , and yeast protein. These proteins were prepared accord- 

 ing to the standard published methods, particular care being 

 taken to have the proteins, in so far as it was possible, free from 

 vitamines. 



HYDROLYSIS OF THE PROTEINS. 



All of the above proteins were hydrolysed by boiling them 

 with seven parts of concentrated hydrochloric acid (specific 

 gravity 1.19) for eight to ten hours. After cooling, the humin 



