Streptococcic Mastitis. 33 



ence of streptococci or staphylococci, and in these mixed infections 

 causes severe necrotic inflammations of the udder, and may con- 

 tinue to produce chronic mastitis in the affected udder tissue after 

 the disappearance of the other bacteria. 



Other forms of mastitis are produced by tuberculosis and 

 actinomycosis, and they usually result through emboli of the in- 

 fective agents. They may be of a traumatic origin (actinomycosis) 

 induced by irritation with particles of straw, or barley beards. 



Furthermore all possible infective agents, as for instance 

 the Bacillus necrophorus, may be found in inflammations of the 

 udder, either independently or as mixed infections. 



Only the more important infections of the parenchyma will 

 be described here. 



Streptococcic Mastitis. 



By far the most widely spread type is the Streptococcic mas- 

 tisis, described by Sven Wall as streptomycosis of the udder. 



The works of Bergey, Craandijk, Trommsdorff and Rullmann, 

 Kunze, Eussell and Hoffmann, Savage, Riihm, and Ernst give gen- 

 eral information on this condition. The disease is either sporadic 

 or epizootic among the animals of a stable according to the stable 

 conditions. The disease may attain an especially wide distribu- 

 tion when the secretion of the affected quarter is milked upon the 

 floor or into the bedding, and the milkers fail to wash their hands, 

 both bad practices which, it is to be regretted, are quite common. 



Zschokke, Jensen, Bang, and Sven Wall proved experi- 

 mentally that bacteria injected into the cistern penetrate even into 

 the farthest alveoli in from 2 to 24 hours. 



By inoculating with strains of streptococci of different ori- 

 gin varying reactions may be produced in the udder (Bang: Strep- 

 tococci equi and Streptococci agalactice; Gminder : streptococci of 

 the stable air and of infectious vaginal catarrh). The manifesta- 

 tions also vary after the injection of individual strains into the 

 same animals, and from injections of the same strain into various 

 animals. In other words the course of the disease varies in ac- 

 cordance with the virulence of the organism, the resistance 

 of the body, and the extent of the local invasion which again is 

 influenced by the lactation period. According to de Bruin fresh 

 milking animals more frequently become affected with the acute 

 form having inflammatory manifestations, while in old milking 

 animals the disease confines itself mostly to the altered appearance 

 ot the secretion. 



The result of the disease is that sooner or later the affected 

 part of the gland becomes destroyed. 



Sometimes the streptococci remain for weeks in the folds of 

 the mucous membrane of the cistern without infecting the par- 

 enchyma ; in other cases again the entire quarter quickly becomes 

 affected. Unfortunately the disease does not often subside even 



