206 PYOGENIC BACTERIA IN DOMESTIC ANIMALS 



represent grayish-white, fibrous, lardaceous connective-tissue masses 

 in which smaller areas of cellular vascular granulation tissue are found, 

 often with small cavities and fistulous tracts containing varying 

 amounts of pus, and in the latter the peculiar zoogleal masses of the 

 Micrococcus ascoformans. Botryomycosis is nearly always a wound 

 infection. It may originate at any break in the surface made by the 

 harness, and it frequently begins in castration wounds. The process 

 extends from the cutaneous and subcutaneous tissue into the lymph 

 glands and muscles, where it may lead to a botryomycotic myositis. 

 In castration wounds the botryomycotic masses along the seminal 

 cords sometimes assume a large size and a mushroom shape. Botry- 

 omycotic tumors of the chest and shoulders of the horse weighing 

 from fifty to one hundred pounds have been reported. Tumors of 

 smaller size have also been found at the lips, conchse of the ears, 

 mammary glands, anus, tail, etc. 



Morphology and Staining Properties. The zoogleal masses found in 

 the pus and the tissues can be seen with the naked eye as pinhead- 

 sized, yellowish-white bodies. When examined microscopically they 

 appear mulberry-shaped, and are found to consist of large, densely 

 crowded cocci. They are contained in and surrounded by a mass of 

 protoplasm, and for this reason are known as zoogleal masses. The 

 protoplasmic envelope or capsule is the thicker the larger the colony 

 of cocci. The individual cocci are comparatively large, i. e., 1 to 1.5 

 micra in diameter. They stain best with anilin-water-gentian violet. 



Cultural and Biologic Properties. The Botryococcus ascoformans 

 can be easily cultivated on gelatin and potatoes, less easily on agar. 

 It liquefies gelatin. The artificial cultures never show the zoogleal 

 masses, which are seen in the infected tissues and pus. In pure 

 cultures the organism closely resembles the Staphylococcus pyogenes 

 aureus, but the preponderance of evidence is that the botryococcus is a 

 distinct organism and not a variety. While it is true that cultures of 

 the botryococcus, when inoculated into a horse, may produce either 

 a simple suppuration or a botryomycosis, injections of the Staphy- 

 lococcus pyogenes aureus into any animal have never been known 

 to produce a botryomycosis. 



Experimental Infection. Guinea-pigs after inoculation with the 

 Botryococcus ascoformans die from septicemia. In sheep and goats 

 subcutaneous infection produces an edema, sometimes with necrosis 

 of the skin, and occasionally followed by death. Kitt reports that 

 pigeons and ducks die after inoculations. 



PYOGENIC BACTERIA OF CATTLE. 



Suppuration in cattle in a majority of cases is not due to the common 

 staphylococci so frequently found in man and the horse, but to the 

 following special bacteria: 



