368 Strangles. 



which he considers as harmless habitants of the intestinal tract, but which may 

 become harmful umler certain conditions, alone or in connection with colon ba- 

 cilli. 



Tenacity. Streptococci belong to the more resistant bacteria. They resist 

 drying, especially in pus or l)lood, for f-everal weeks. A temperature of 70-75 de- 

 grees destroys them in 1 hour, while frozen bouillon cultures are still active after 

 two days. They are destroyed inside of 15 minutes by sulphuric acid 1:150, sodium 

 hydrate 1:85, corrosive sublimate 1:1500, iron sulphate 1:125, carbolic acid or 

 lysol 1:200, and creolin 1:80 (Lingelsheim). 



Pathogenicity. Subcutaneous inoculations of a pure cul- 

 ture, or pus from a gland produces in mice a purulent inflam- 

 mation of the subcutaneous connective tissue and lymph glands, 

 also metastatic abscesses in the internal organs. Rabbits are 

 less susceptible, and guinea pigs to a still lesser degree. Intra- 

 peritoneal inoculations, however, are fatal to rabbits (Ludwig), 

 while cutaneous inoculations into the ears produces erysipelas 

 (Jensen & Sand). A subcutaneous injection in horses causes a 

 purulent inflammation at the point of inoculation, with partial 

 necrosis of the tissues; an injection of pure culture into the 

 nasal cavity, especially if the mucous membranes have been x^re- 

 viously rul)bed, develops an acute nasal catarrh, and suppura- 

 tion of the submaxillary Ijanph glands; therefore the typical 

 clinical manifestation of strangles (Schiitz). Rubbing pus con- 

 taining streptococci upon the scarified skin produces a febrile 

 vesicular dermatitis, which heals within a short time. The infec- 

 tion of cattle is sometimes successful (Jolly & Leclainche). 



Natural Infection. The results of the experiments just 

 alluded to indicate that the causative factor of strangles, when 

 reaching the nasal cavities, produces there a purulent or muco- 

 purulent inflammation of the mucous membrane ; but there exists 

 also a possibility that the virus may primarily attack the tissues 

 from other organs, especially from the pharynx and the intes- 

 tines. Schiitz based the belief on his microscopical examinations 

 of liver sections from mice, that streptococci penetrate the walls 

 of the blood capillaries, and that therefore the infection may 

 take place through the uninjured mucous membranes. As strep- 

 tococci may easily colonize in the numerous recesses of the nasal 

 cavities, where they may continue to multiply, the nasal secre- 

 tion of infected animals may transmit the disease to a healthy 

 horse when it reaches its nasal cavities. 



Under natural conditions the infection occurs usually 

 through the nasal secretion or pus from affected animals enter- 

 ing, directly or by transmission with contaminated substances 

 (food, drinking water), the upper air passages of a healthy horse 

 (nasal cavities, buccal cavities), where it adheres to the mucous 

 membrane. It is also very possible that infection takes place 

 through the uninjured mucous membrane, where the bacteria 

 very likely penetrate the excretory ducts of tlie mucous glands. 

 The disease which usually attacks all the colts in a stable, could 

 hardly be explained otherwise ; on the other hand the infection 

 is favored by conditions of the mucous membranes in which 



