BLASTOMYCETES 389 



not involved, the disease differing in this respect from the lymph- 

 angitis of the horse. The course of the disease is usually chronic, 

 and it may persist for years, new ulcers appearing successively on 

 various parts of the body. Generalization has been reported in a 

 considerable number of cases. The skin lesions have sometimes 

 been confused with those of syphilis and tuberculosis. Primary 

 infection of the lungs has been shown in several cases. 



Immunity. No method of establishing immunity has been 

 developed. 



Bacteriological Diagnosis. This may be accomplished by direct 

 microscopic examination of the pus. Phalen and Nichols state 

 that the organism may be most easily demonstrated by treating 

 unstained sections with potassium hydrate and mounting in 

 glycerin. 



Transmission. It is supposed that infection sometimes occurs 

 through wounds, but several instances have come to light in which 

 the infection was primarily pulmonary and the skin lesions sec- 

 ondary. 



Blastomyces coccidioides 



Synonym. Oidium coccidioides. 



Disease Produced. Blastomycosis, so-called coccidioidal granu- 

 loma in man. 



Posades and Wernecke, in 1892, first reported a case of so- 

 called coccidioidal granuloma from Argentina. In the United 

 States the disease has been recorded principally from California, 

 particularly in the San Joaquin Valley. 



Morphology. This form is of particular interest, because the 

 budding or true blast-only ces form very rarely occurs in the tissues, 

 and multiplication is almost wholly through sporulation. The 

 organism in the tissues is spherical and doubly contoured. It may 

 reach a diameter of 30 u or even more. Budding forms have been 

 recorded from pus. In artificial media the organism resembles 

 a mold, but budding forms may be observed. The method of 

 reproduction in tissues, by the formation of spores within the 

 mother-cell and their liberation by a rupture of the cell membrane, 

 has led some investigators to believe that the organism is roally 

 a protozoan. However, sporulation of this general type occurs 

 in the yeasts. The question seems to be definitely settled in 



