386 VETERINARY BACTERIOLOGY 



pearance in the course of a month, and finally attain to a diameter 

 of 1 to 4 mm. The colony is wrinkled, and can be removed only 

 with difficulty. Growth upon gelatin is essentially similar. 

 Potato seems somewhat more favorable, and growth occurs more 1 

 rapidly, but is of the same character as on agar. 



Physiology. The organism is aerobic. Growth occurs at 

 room-temperature as well as at 37. It does not liquefy gelatin. 

 Sugars are not fermented with production of either acid or gas. 



Pathogenesis. Experimental Evidence. Guinea-pigs and rab- 

 bits are not easily infected with pure cultures. Typical lesions 

 have been produced in the horse by Tokoshige. They are readily 

 produced by the injection of pus from natural infections. 



Character of Disease and Lesions. The disease in the horse 

 shows a marked superficial resemblance to farcy. The infection 

 progresses through the subcutaneous lymphatics and forms dis- 

 tinct nodules. These may suppurate. Metastatic infection of 

 the internal organs occasionally occurs. 



Immunity. No practicable method of immunization has been 

 developed. 



Bacteriological Diagnosis. The organism may be readily 

 observed in a mount of the pus from a lesion stained by Gram's 

 method. 



Transmission. It is supposed that infection is traumatic, that 

 the organism gains entrance through cutaneous lesions. The 

 disease not highly contagious. 



Blastomyccs dermatitidis 



Synonyms. Saccharomyces dermatitidis', Oldium dermatitidis. 



Disease. Blastomycetic dermatitis in man. 



Busse, in 1894, first described an organism of this group as the 

 cause of a fatal infection in man. Gilchrist, in 1896, found a 

 similar organism as the cause of a dermatitis in man. Since that 

 time the organism has been repeatedly isolated and studied. 



Distribution. Blastomycotic dermatitis has been reported 

 from the United States, the Philippines, and Europe. 



Morphology and Staining. It is probable that several distinct 

 species have been grouped together; that is, not all cases have 

 shown morphologically identical organisms to be present. They 



