F. W. TANNER 499 



which conidia were formed. Thus, Sporobolomyces were believed to be Basidiomycetcs, 

 an opinion not concurred in by Lohwag' and Guilliermond.^ 



Lewis^ has reported a filterable yeast under the provisional name of Schizosac- 

 charomycesfiltrans. This is the first report that filterable stages may occur among the 

 yeasts. Yeasts are many times larger than bacteria. Filterability of yeasts is more 

 surprising than of such a small organism as the Dialister pneiimosintes of Olitsky and 

 Gates. In the discussion of his results Lewis considered various explanations for his 

 observations. The fungus reproduces by fission and if placed with the yeasts would 

 be a Schizosaccharomyces. Lewis seems somewhat undecided about the identity of 

 his organism. This is quite proper both from the standpoint of the characteristics 

 which he has presented as well as from the characteristics which have been estab- 

 lished for Schizosaccharomyces. To one who has followed some of the more recent 

 contributions to the morphology of bacteria, the evidence presented by Lewis is not 

 convincing. In the first place, the size of Lewis' organism is not as great as that of the 

 average yeast cell, nor are his illustrations definitely demonstrative. The forms 

 portrayed are not at all unlike the transitional forms which have been reported by 

 many of those engaged in the study of life cycles, cytomorphosis, etc., of the Eubac- 

 teria. 



ACCESSORY SUBSTANCES ("bIOS") 



The question of whether or not yeasts need accessory substances still holds the 

 interest of a number of investigators. The "bios" question was reviewed in 1925 by 

 Tanner.'' It was then suggested that the term "vitamin" be not used for the yeast 

 growth-accelerating substance but that discussion of accessory substances for the 

 yeasts center about the term "bios" proposed by Wildiers in 1901. This has been 

 done because the term "vitamin D" is commonly used for the antirachitic vitamin of 

 MacCollum and not for the yeast growth-accelerating substance, if one exists, as was 

 suggested by Funk.^ In 1925 Funk proposed a new nomenclature for accessory sub- 

 stances, using the term "vitamin D" for the yeast growth-promoting substance. 

 MacDonald'' argued that the term "bios" be retained for various reasons: It was pro- 

 posed ten years before vitamins were recognized; it has not been identified chemically; 

 it is questionable whether bios is a vitamin; and, finally, bios now has a well-estab- 

 lished literature of its own. 



One of the few announcements of the isolation of a pure bios is that by Eddy, 

 Kerr, and Williams^ in 1924. Their crystalline substance was said to have properties 

 of the bios of Wildiers. 



In minute doses (0.005 i''"'g- per cc.) it stimulated the multiplication of yeast. However, 

 Eddy and his colleagues found a variation of this stimulating ability depending on the 

 species used. It had less effect on top yeasts than on bottom yeasts. The melting point of 



' Lohwag, H.: Ann. mycoL, 24, 194-201. 1926. 



^ Guilliermond, A.: Compt. rend. Acad. scL, 184, 617. 1927. 



3 Lewis, P. A.: J. Exper. Med., 45, 277-90. 1927. 



■» Tanner, F. VV.: Chem. Rev., i, 397-412. 1925. 



5 Funk, C: Science^ 62, 157-58. 1925. 



^MacDonald, M. B.: ibid., 63, 187. 1926. 



'Eddy, W. H., Kerr, R. W., and Williams, R. R.: /. Am. Chem. Soc. 46, 2846-55. 1924. 



