PRINCIPLES OF VETERINARY SURGERY 519 



served in the horse, the disease has nevertheless been seen 

 in the ox, the hog, and even in man. 



ETIOLOGY— AND PATHOGENESIS.— The disease 

 is caused by a special parasite, which, when examined by a 

 low power, appears in the form of colonies of micrococci in 

 rounded muriform masses of variable dimensions, each of 

 which seems to be surrounded by a gelatinous capsule. It is 

 easily stained with picro-carmin, and sometimes it presents 

 the aspect of granular discs. Rabe cultivated the fungus on 

 potato and gelatinized peptone. On gelatine the botryomyces 

 give white, round colonies which in the course of time be- 

 come grey. On glycerinated gelose the colonies are orange- 

 colored and on potato they are yellowish and emit an odor of 

 ripe strawberries. 



On microscopic examination of the cultures, the parasite 

 is seen in the form of micrococci measuring about i micron, 

 collected in heaps. It is easily stained by all aniline dyes, 

 but especially by Loefifler's methylene blue. 



Experimental inoculation has been successful in the 

 horse. Rabe has successfully produced lesions analogous to 

 those developing spontaneously. In other species, — cavies, 

 sheep and goats, — the experimental inoculations have only 

 caused necrotic inflammatory processes. Under natural con- 

 ditions it is not doubted that inoculations occur through 

 wounds of castration, or cutaneous abrasions caused by de- 

 fective harness, collars or halters. The tumors are frequent 

 in the spermatic cord, on the shoulder, in the parotid region, 

 at the elbow in animals that lie cow-fashion, on the lips, on 

 the tail, between the thighs, in the pasterns, in the udder, and 

 on the mucous membranes. Wester reports the case of a 

 horse that very clearly demonstrates the possibility of in- 

 fection by the harness. The collar of a horse affected with 

 botryomycosis, when placed on another horse, inoculated 

 the latter in the same part of the body. 



