YEASTS AND MOLDS 231 



Cultivation. In liquid media containing vegetable infu- 

 sions growth occurs best. Temperature, of 37 C. most 

 suited. The colonies near the surface become colored red. 



A gar. Glazed colonies, at first colorless, then rose-colored, 

 about the size of a pea, with the central part umbilicated and 

 pale. Gradually the rose color fades. 



Acid Potato. A slow and meager growth. 



Pathogenesis. Only local reaction has been caused by 

 inoculation in animals. In man the disease usually follows a 

 slight injury and attacks the leg or foot, slowly forming a 

 nodular growth, which in the course of months or a year 

 begins to soften and ulcerate, and with the seropus are dis- 

 charged numerous little granules, some black, some pink, 

 containing mycelia. The limb becomes much deformed, the 

 tissue vascularized, and the degenerated area filled with the 

 streptothrix filaments. 



Staining. The organism itself stained with ordinary 

 stains. Gram's method for the tissue. 



Nocardia (Streptothrix) Farcinica.(Nocard) ; Bovine 

 Farcin du Bosuf . Origin. A disease affecting cattle, and 

 giving rise to tubercle-like lesions in the lungs, liver, and 

 spleen. Common in France. 



Form. Small interwoven mass of threads arranged in 

 tufts found in the centers of the tubercles. 



Culture. At body- temperature in various media. 



Bouillon. Colorless masses, irregular in size and shape. 



A gar and Gelatin. Small, rounded, opaque colonies, 

 thicker at the periphery. 



Potato. Rapid growth of pale-yellow, dry scales, consist- 

 ing of many spores. 



Pathogenesis. Pure cultures introduced into the perito- 

 neum of guinea-pigs give rise in nine to twenty days to 

 tubercle-like lesions. Subcutaneous injections cause abscesses 

 with secondary involvement of the lymphatics, ending in 

 recovery. Dogs, horses, and rabbits are immune. 



Staining. Wright's double stain for tissues; also Gram's. 



Plant Diseases due to Bacteria. There are a great 



