THE VITAMINES IN THE VEGETABLE KINGDOM 55 



mann (I.e. 126) developed a somewhat similar method simultaneously 

 with the American investigators. 



There seems to be no unanimity as to whether or not yeast 

 requires extraneous vitamine for growth. Thus, Fulmer, Nelson 

 and Sherwood (129a) believe that yeast does not require vitamine 

 B for growth. These authors were able to grow yeast on a 

 synthetic culture medium supposedly free from' vitamine. How- 

 ever, their findings are not as definite as their conclusions. Nelson, 

 Fulmer and Cessna (129b) have found that if the brewer's yeast 

 in a synthetic diet was replaced by yeast grown on a synthetic 

 medium in the absence of vitamines, the growth of rats proceeded 

 normally, showing that the above yeast synthetized its own 

 vitamine. Working with pigeons, Harden and Zilva (129c) also 

 found that yeast synthetizes vitamine on a synthetic medium 

 but to a lesser extent than in the presence of vitamine. Funk and 

 Dubin (129d) were unable to corroborate the findings of Fulmer, 

 Nelson and Sherwood, using the medium F described by the latter. 

 Poor yeast growth was obtained in the absence of vitamine while 

 a marked improvement was noted when vitamine was added. These 

 same conclusions were reached by Eddy, Heft, Stevenson and 

 Johnson (129e). MacDonald and McCollum (129f) maintain 

 also that they can grow yeast on a pure nutrient medium in the 

 absence of vitamine B. However, they obtained better growth 

 with this vitamine added. This subject became a matter of con- 

 troversy between Ide (129g) and MacDonald and McCollum (129h), 

 the former maintaining that yeast can grow in two ways slow 

 growth without bios and rapid growth in the presence of bios, 

 while the latter hold that there is no necessity for assuming the 

 existence of a specific substance promoting the growth of yeast. 

 We personally are in accord with the view of Ide that at least cer- 

 tain yeast species do require a specific substance for growth. A 

 number of procedures such as improving the inorganic moiety of 

 the medium and the addition of glucose or amino acids may give 

 slight increase in growth but not to be compared with that ob- 

 tained on the addition of vitamine. Until we know how many new 

 cells can grow out of a few broken down cells, this question, as to 

 whether yeast can grow without vitamine, must be left open. From 

 the foregoing, it would seem that yeast cells can produce vita- 

 mines, if an original stimulus is provided. 



