796 



Blastomycosis 



by greatly diluting the culture material, so as to separate the 

 contained organisms widely. 



Many culture-media prove appropriate, glycerin agar-agar and 

 agar-agar containing i per cent, of dextrose being excellent. When 

 once isolated the organism is easily kept growing by transplanting 

 every month or two. 



The colonies appear in a few days as small, round, hemispheric 

 dots with numerous prickles about the surfaces. Later they have a 

 moldy appearance from the development of aerial hypha. They are 

 almost purely aerobic, those on the surface growing well, those 

 deeply seated in the medium scarcely at all. 



Agar-agar Slants. — These at first show a creamy white layer that 

 becomes quite thick, and is moldy and fluffy on the surface. After 



Fig. 321. — Blastomyces derma titidis. Budding forms and mycelial growths 

 from glucose agar (Irons and Graham, in "Journal of Infectious Diseases"). 



a few weeks the agar-agar begins to turn yellow and later may be- 

 come brown, though the growth itself remains white and unchanged. 

 The growth is firmly attached to the agar. When old, the growth 

 wrinkles. 



Bouillon. — The growth is not luxuriant. The medium is not 

 clouded and contains fluffy flocculi of stringy viscid material. 

 Sugars added to the medium may be fermented. 



Gelatin. — Growth takes place with aerial hypha. Liquefaction 

 does not occur or is very slow. 



Potato. — Abundant growth with aerial hypha. 



Milk. — Not coagulated, not acidified, slowly digested. 



There is some diflSculty in describing the cultures, as different 

 authors describe them quite differently, evidently having different 

 organisms or different strains under observation. 



