VARIATIONS IN DIFFERENT CHARACTERS 39 



sputum during life, and from the bronchi post-mortem, a typical 

 Candida albicans was isolated. But from abscesses in the kidneys 

 and other viscera, there was obtained a yeast which had the same 

 fermentation reactions, but which failed completely to form my- 

 celium under any conditions. The second case was a child which 

 had suffered for some years from oral and intestinal moniliasis, with 

 repeated attacks of moniliid. From the mouth and feces again C. 

 albicans was isolated repeatedly. At autopsy caseous nodules were 

 found in the peribronchial glands and in the lungs near the hilus. 

 From these were obtained pure cultures of C. Knisei, non-virulent 

 and non-fermentative. It seems very unreasonable to suppose that 

 a simultaneous infection with two closely related species occurred in 

 each of these three cases. It seems much more likely that in all of 

 them the original fungus had undergone a variation within the in- 

 fected tissues. 



Variations in Different Characters. The variations considered so 

 far have concerned mainly the texture of the colony, which is de- 

 termined largely by the morphology of the fungus. Variations have 

 been observed in a variety of other characters, as pigmentation, 

 virulence, and biochemical activities. It would require too much 

 space adequately to review all the growing literature on variations 

 in fungi. A few papers will be cited, from which further references 

 may be obtained. 



Chodat ^ made extensive studies of variants of Aspergillus ochra- 

 ceous and Phoma alternariaceum, the latter giving rise to five dis- 

 tinct races. Both morphological and physiological characters varied. 

 Some of the new races were permanent, others reverted. Dodge ^^ 

 obtained an albino race of the red mold, Neurospora sitophila. 

 Emmons ^- described variations in color and texture of the colonies 

 of Microsporum gypseiim. Biltris ^ also described variations of a 

 dermatophyte. Trichophyton mentagrophytes. Wiltshire ^^ found 

 sectors in cultures of Alternaria which gave rise to conidia of the 

 Stemphyllium type. Fabian and IMcCullough " described variations 

 in yeasts, Mackinnon ^^ in Candida albicans. There have been some 

 studies of variations in virulence and host-specificity, but these have 

 been confined to the plant pathogens, especially to smuts and rusts. 



The intrinsic mechanisms which give rise to variations in fungi are 

 undoubtedly very complex, and far from being fully known. It now 

 seems probable that there occur all the mechanisms known to occur 

 in higher organisms, involving on the one hand the variations caused 

 by a loss or alteration or instability of genes, which are called muta- 

 tions, and on the other hand those due to the combinations and 



