CHAPTER XLI1. 

 STREPTOCOCCI ANIMALIUM. 



I, Streptococcus egui. 

 II, Streptococcus mammitis bo vis, p. 613. 

 Ill, Micrococcus mammitis of ewes, p. 615. 



I. Streptococcus equi. 



(The streptococcus of strangles.) 



STRANGLES in horses is caused by a streptococcus discovered by Schiitz, 

 which is found also in a number of other though very different clinical con- 

 ditions in the horse. This organism has been confused with the equine 

 pasteurella which, as a matter of fact, prepares the way for the streptococcus 

 of Schiitz. 



It has been pointed out already (Chap. XXVIII.) that in a large number 

 of conditions originated by members of the pasteurella group the original 

 infecting agent disappears early in the course of the disease, so that bacterio- 

 logical examination reveals only the presence of the secondary or associated 

 infection, in this case the streptococcus. 



Strangles is chiefly a disease of young horses from 1-5 years old. The common 

 symptoms are : nasal catarrh, swelling and suppuration of the glands in the sub- 

 maxillary space (strangles) and lymphangitis. The lungs and pleurae are not infre- 

 quently involved and the pleurisy may be of the purulent variety. Sometimes the 

 disease may become generalized, in that case there is septicaemia with metastatic 

 abscesses. The streptococcus can be found in the discharge from the nose, in the 

 enlarged glands, in the abscesses, in the pus from the pleura, in the pulmonary 

 lesions, etc. 



The streptococcus equi though differing from them in certain respects is 

 very closely related to the streptococci hominis. It grows well in the filtrate 

 of a broth culture of the streptococci hominis (p. 598). Marmorek's serum 

 has no action upon it. 



SECTION I. EXPERIMENTAL INOCULATION. 



White mice. White mice are the animals most susceptible to experi- 

 mental infection. After subcutaneous inoculation an abscess forms at the 

 site of inoculation : this is followed by lymphangitis and enlargement of 

 the related glands, and as in the horse, the lungs and pleurae may become 

 involved and abscesses may form in the internal organs. The streptococcus 

 is found in pure culture in all the lesions : in the blood it only occurs in 



