Botryomycosis. 



673 



by Rivolta & Micellone (1879), Johne (1884) and by Rabe (1886) 

 in fistulae of the spermatic cord of horses, as well as in tumors of 

 the withers and pectoral region. Since then the frequent occurrence 

 of this disease has been confirmed by numerous observations. In more 

 recent years Kitt, de Jong, Galli-Valerio and Parascandolo & Meis made 

 special bacteriological studies of this organism. 



Etiology. The botryomyces equi, Bollinger (Discomyces 

 equi, Rivolta; Micrococcus botryogenes, Rabe; Micrococcus 

 ascoformans, Johne; Botryococcus, Poncet & Dor) appears in 

 the diseased tissues in the form of mulberry-like or grape-like 

 clusters, 1.0 mm, in diameter. The individual elements in these 

 clusters are surrounded by a homogenous gelatinous capsule of 

 sharp contour, thus forming zoogloea masses (Fig. 110 and 111). 



Staining. These cocci stain readily in aqueous aniline dyes as 

 well as according to the Gram-Weigert method. The gelatinous capsule 

 does not take the stain. The organisms are very resistant to the action 

 of alkalies and acids. 



Culture. On gelatin the broken zoogloea give rise to the develop- 

 ment of colonies, at first silver gray but subsequently grayish-yellow, 

 with a metallic luster, while a white streak may be oliserved to develop 



Fig. 110. Botryomyces equi. Zoog- 

 loea mass from a soft focus. Not Stain- 

 ed. Mag. ca. 100 diam. (according to 

 Rabe). 



Fig. 111. Boctryomyces equi. Section 

 of Zoogloea. Stained according to 

 Gram, a Ground Substance ; 6 Cocci. 

 Mag-, ca. 500 diam . 



along the needle puncture in the depths of the medium, gradually 

 causing the gelatin to liquefy along its course when the colonies sink 

 to the bottom. On potatoes a pale yellowish, hoar-like coating is formed. 

 The cultures emit a peculiar odor recalling that of strawberries. The 

 colonies are composed of micrococci without, however, any characteristic 

 grouping and without hyaline capsules. 



Pathogenicity. Mice are not susceptible in infection ; infec- 

 tion of guinea pigs with pure cultures produces fatal septicemia. 

 Inoculation of sheep and goats is followed by an inflammatory 

 edema occasionally followed by necrosis of the surrounding area 

 of the skin. In horses inoculation of pure cultures produces 



