100 SPECIAL BACTERIOLOGY 



when the discolorization in absolute alcohol is not continued for more 

 than fifteen or twenty seconds, and in two minutes the organism is 

 entirely decolorized. The above reaction with the Gram method 

 differentiates this organism from Fraenkel's pneumococcus, which stains 

 readily by the Gram method. 



Biological Characters. The diplococcus grows on gelatine and 

 agar media at room temperature ; the gelatine is not liquefied, and the 

 growth in both media exhibits nothing characteristic. 



Pathogenesis. Affect mice, guinea-pigs, pigeons, and rabbits, 

 but not fowls or swine. The etiological importance of this organism 

 is established by its constant and characteristic presence in the 

 pulmonary tissues and effusions of affected horses, and by the fact 

 that Schiitz produced typical cases of the disease by injecting healthy 

 horses intrapulmonarily with the diplococcus. The bacteria, 

 according to Von Rust, are present in the nasal discharges of affected 

 horses. Fiedler isolated the diplococcus from the blood of affected 

 animals, and produced the disease on healthy animals by intra- 

 pulmonary injection. 



BOTRIOMYCOSIS. 



Botryomyces (Bollinger) ; Discomyces (Rivolta) ; Botryococcus 

 ascoformans (Kitt) ; Mykodermoid (Johne). 



This parasite is found in the indurated tissue of scirrhus cord of 

 castrated horses, and also in some form of fistulous withers, tumours 

 at the point of the shoulder, and other indurations of the skin and 

 subcutaneous tissue, also in the connective tissue of the pelvic cavity. 

 In the pus of chronic mammitis of the cow (Czoker), and in the 

 lungs, ribs, and pleural cavity ; also in the spermatic cord of swine. 

 MM. Porcat and IT or record four cases in man. Microscopically the 

 parasite appears in grape or mulberry-shaped masses of pale greyish- 

 yellow bodies, about the size of small grains of sand. 



Microscopical Appearances. The individual colonies are formed of 

 granular clusters of symmetrical grains, united by a gelatinous sub- 

 stance, and enveloped within a close-fitting, transparent, colourless 

 membrane, which holds them together. 



Staining Reactions. The parasite stains by the Gram method, 

 and when eosin is used for a contrast, it stains the gelatinous substance. 

 Picric acid has a similar action. 



Biological Characters. When grown on gelatine and potato 

 media, the conglomerated and the envelop formation no longer exist. 

 Gelatine is slowly liquefied ; the developing colonies present first a grey 



