98 SPECIAL BACTERIOLOGY 



colonies appear at first as shiny grey drops ; and after this a dry 

 iridescent coating forms. 



In Bouillon a flocculent white mass develops, finally forming a 

 sediment at the bottom of the tube. 



Pathogenesis. Horses can be inoculated with pure cultures, 

 abscesses forming at the point of inoculation, due to necrosis of the 

 tissues. Inoculation into the mucous membrane of the nose causes 

 typical purulent nasal catarrh, with accompanying inflammation and 

 enlargement of the lymph-glands. Mice are also susceptible to 

 infection when inoculated, an abscess forming at the point of inoculation, 

 accompanied with metastatic suppuration throughout the course of the 

 lymphatic and blood circulations. 



Differential Diagnosis. The disease is differentiated from 

 glanders by experimentally inoculating field-mice, which are highly 

 susceptible to glanders, but immune to strangles. 



The streptococcus of strangles is not a very resistant organism, as 

 white mice inoculated with dried pus remain unaffected. 



STREPTOCOCCUS OF CONTAGIOUS MAMMITIS 

 OF MILCH COWS. 



This is a special form of mammitis occurring in milch cows, 

 described by Nocard and Mollerau. It passes rapidly from one 

 animal to the other. The disease commences at the base of the teats 

 in the form of indurated lumps, which sooner or later invade the 

 whole organ. 



Microscopical Appearances. Round or ovoid micrococci, 1-25 /z 

 long and 1 //, broad, occurring in long straight or undulating chains. 

 These characteristic chains are found in the milk and in the walls of the 

 excretory ducts. They can be stained by the ordinary dyes, but not by 

 the Gram method. The growth of this organism in cultures is checked 

 by a trace of boric acid. By means of injections of 100 grains of 4 per 

 cent, tepid solutions of boric acid into the teats of affected udders, 

 Nocard and Mollerau succeeded in arresting the extension of the disease. 

 The organism is also destroyed by a 3 per cent, solution of carbolic acid. 



Biological Characters. On Gelatine Plates. Small, round, non- 

 liquefying granular colonies of slow growth. 



In Gelatine Stab Cultures. In the form of a nail. 



On Agar-Agar it grows badly. 



Bouillon is very soon clouded. 



Milk becomes acid and is coagulated, 



