44 Structure and Classification of Micro-organisms 



tivated and used in the manufacture of fermented liquors 

 and bread. They grow well in fermentable culture-media 

 and most of them also grow upon the ordinary laboratory 

 culture-media. Many varieties, some of which produce red 

 or black pigment, some non-chromogenic, are known. They 



Fig. 7. Blastomycetes dermatitidis. Budding forms and mycelial 

 growth from glucose agar (Irons and Graham, in "Journal of Infectious 

 Diseases"). 



play very little part in the pathogenic processes. Burse has 

 observed a case of generalized fatal infection caused by an 

 yeast that he calls Saccharomyces hominis. Gilchrist, 

 Curtis, Ophuls, and others have seen localized human infec- 

 tions by blastomycetes. (See Blastomycetic dermatitis.) 



THE OIDIA. 



These organisms seem to occupy a place intermediate be- 

 tween the yeasts and the molds the blastomycetes and the 

 hyphomycetes. In certain stages they appear as oval cells 

 which multiply by gemmation, but instead of becoming sep- 

 arated, hang together. At a later stage of development they 

 grow into long filamentous formations suggesting the mycelia 

 of molds, but being less regular. Certain cells also develop 

 as reproductive organs. 



