Lesions 823 



remains white and unchanged. The growth is firmly at- 

 tached 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. Lique- 

 faction does not occur or is very slow. 



Potato. Abundant growth with aerial hypha. 



Milk. Not coagulated, not acidified, slowly digested. 



There is some difficulty in describing the cultures, as differ- 

 ent authors describe them quite differently, evidently having 

 different organisms or different strains under observation. 



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 vulgar is, other cases present an 

 exaggeration of the ulcerative element. Cases have also 

 been mistaken for syphilis. The intractable character of the 

 lesions is suggestive, and the finding of the micro-organisms in 

 the viscid pus is pathognomonic. 



Upon section the lesions still resemble lupus and other tu- 

 berculous 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 infection is not known. 



