Cultivation 



821 



and transparent, as frequently granular and vacuolated. 

 From these buds may grow, as in the yeasts ; or hypha may 

 form, as in oi'dium. In artificial cultivations the hypha may 

 form a tangled mycelium. 



Staining. The organisms are usually better found with- 

 out staining. They do not stain with aqueous anilin dyes, 

 but are penetrated by warm thionin, alkaline methylene-blue, 

 and polychrome methylene-blue. In sections of tissue 

 stained with hematoxylon and eosin they show as uncolored 



Fig. 277. Blastomyces dermatitidis. Budding forms and mycelial 

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

 Diseases"). 



circles; with thionin and alkaline methylene-blue they may 

 take a blue color. 



Cultivation. The organism grows readily upon artificial 

 media when once started, but the primitive culture is difficult 

 to secure, because the cocci and other associated organisms 

 are more numerous than the blastomyces and outgrow it. 

 It seems most satisfactory to first infect a guinea-pig with the 

 organism from the skin, and then start the cultivation from 

 its lesions than to attempt it directly from the pus from 

 human dermal lesions. When the human lesions are internal, 

 pure cultures are easily started. 



Gilchrist and Stokes* were able to start cultures directly 



* "Journal of Experimental Medicine," 1898, in, 53. 



