Transmission 



Pathogenesis. The organisms are pathogenic for guinea-pigs, 

 rabbits, and dogs, in which an abscess, not infrequently followed by 

 a generalized infection, takes place. 



Lesions. The human lesions vary somewhat. Gilchrist's first 

 case resembled lupus vulgaris, other cases present an exaggeration 

 of the ulcerative element. Cases have also been mistaken for 



Fig. 314. Cultures of Blastomyces dermatitidis upon solid culture- media 



(Montgomery). 



syphilis. The intractable character of the lesions is suggestive, and 

 the finding of the micro-organisms in the viscid pus ispathognomonic. 



Upon section the lesions still resemble lupus and other tuberculous 

 lesions, but here again the absence of tubercle bacilli and the 

 presence of the blastomyces enable diagnosis to be made. 



Transmission. -The disease is transmissible. The source of in- 

 fection is not known. 



