130 PHYSIOLOGY OF YKASTS (Continued) 



seems to be indicated by the investigations of Williams l and Bach- 

 mann. 2 Williams presents data to show that water-soluble vitamine 

 may be necessary for the growth of yeasts themselves. Williams used 

 the development of a single cell of yeasts as the indication of the 

 presence or absence of vitamine. Substances which were known to 

 be rich in vitamine were also found to be rich in the yeast growth-pro- 

 moting substance. Williams believes that these substances which 

 stimulate yeast development are the same as those which prevent 

 beri-beri. In a synthetic solution alone, a cell of yeast developed very 

 slowly. Under identically the same conditions, with the exception of 

 the addition of one part in 60,000 of growth-promoting substance, 

 many more cells were formed from the single cell. Bachmann found 

 that water-soluble B vitamine was quite necessary for vigorous de- 

 velopment of a yeast isolated from canned pears. Both papers bear 

 out the contention of Wildier, 3 an earlier worker, who found that some 

 substance, to which he gave the name " bios," was necessary for vig- 

 orous development of yeasts. 



1 Williams, R. J. 1919. The Vitamine Requirement of Yeast. A simple 

 biological test for vitamines. J. Biol. Chem. 38 (1919), 465-86. 



2 Bachmann, F. M. Vitamine Requirements of certain yeasts. J. Biol. 

 Chem. 39, 235-58. 



3 Wildier, E. Nouvelle substance indespensible au developpement de la levure. 

 La Cellule, 18 (1901) 313. 



