SYMBIOSIS OF YEASTS 129 



wonder whether symbiosis in yeasts may not be explained in part on 

 the basis of vitamines, as has been suggested by certain pieces of 

 research for the bacteria. 



Vitamines in Yeast : The importance of "accessory substances," 

 the so-called " vitamines," in the treatment of certain deficiency 

 diseases, has caused investigators to examine different substances for 

 them. While our knowledge, with regard to vitamines, seems to be 

 in a transitory state, it may be advisable to mention a few of the 

 more important papers on the presence of them in yeasts. Funk l 

 isolated 2.5 grains of vitamine fraction from 100 kg. of dried yeast. 

 When this was injected in the muscle of a pigeon suffering from poly- 

 neuritis, complete recovery followed. This original substance was fur- 

 ther fractionated. Some of these were thought, at that time, to be 

 nicotinic acid. Seidell 2 found that brewers' yeast was the cheapest as 

 well as the richest source of vitamines. The yeast cells are dried hy- 

 draulically and allowed to autolyze at 37.5 C. for 48 hours. After 

 cooling, the liquid is filtered. In this clear filtrate will be found about 

 50 per cent of the raw material, and 23 per cent of the total solids. 

 One cc. of this injected into a paralyzed pigeon caused relief in an 

 hour and a return to normal condition in 12 hours. Seidell 3 stated 

 later that the autolytic process influenced the power of the vitamine. 

 Emmett and McKim 4 found that the yeast vitamine of Seidell should 

 be accompanied by vitamine containing foods in order to accomplish 

 normal gains in weight and complete recovery. Hawk 5 and his col- 

 leagues, in another connection, have found that yeasts are decidedly 

 beneficial for treating skin diseases. Improved conditions resulted 

 in many cases from ingestion of yeast, where autogenous vaccines 

 caused no relief. In many cases there was a general improvement in 

 the condition of the patient " quite unassociated . . . with the partic- 

 ular disease in question." This might indicate that some essential 

 or beneficial substance was added to the diet through the ingestion 

 of the yeast. 



That vitamines may be necessary for the development of yeast, 



1 Funk C. Studies on Beri-beri. Further facts concerning the chemistry 

 of the vitamine fraction from yeast. Brit. Med. J. 1913, I, 814. J. Physiol. 46, 

 173-9. 



2 Seidell, A. Vitamines and nutritional diseases. Public Health Reports, 

 31, 364-70, 1916. 



3 Seidell, A. The vitaminic content of brewers' yeast. Jour. Biol. Chem. 

 29, 145-54, 1917. 



4 Emmett, A. D. and McKim, L. H. The value of the yeast vitamine frac- 

 tion as a supplement to a rice diet. J. Biol. Chem. 32, 409-19, 1917. 



5 Hawk, P. B. et al. The use of bakers' yeast in the diseases of the skin and 

 of the gastrointestinal tract. Jour. Amer. Med, Assn. 69 (1917), 1243-1247. 



