388 



VETERINARY BACTERIOLOGY 



of agar. The addition of dextrose to the medium somewhat in- 

 creases the luxuriance of the growth. In bouillon a fluffy, mold- 

 like colony or a granular sediment develops without any evidence 

 of the diffuse clouding generally found in yeast cultures. Gelatin 

 is not liquefied. Milk may or may not show coagulation and 

 slight digestion of the casein. Potato is a favorable medium. 



Physiology. Growth occurs at room-temperatures, but some- 

 what more luxuriantly at 37. The organism is aerobic and facul- 



Fig. 170. Blastomyces dermatitidis (Hamburger, in " Journal of Infectious 



Diseases"). 



tative anaerobic. Gas and acids are not produced in carbo- 

 hydrate media. 



Pathogenesis. Experimental Evidence. Guinea-pigs and rab- 

 bits may be infected, with production of either a local abscess or 

 generalized blastomycosis. The lesions resemble in their essential 

 characters those found in the human body. 



Character of Disease and Lesions. In man a papule generally 

 appears upon one of the extremities, the face, or, more rarely, 

 elsewhere. A viscid pus is exuded, and there is commonly con- 

 siderable enlargement. Healing with an abundant formation of 

 cicatricial tissue gradually occurs. Usually the lymphatics arc 



