58 MASTITIS OF THE COW 



number of chains of cocci. Other changes were the same 

 as above described. 



Foui' days after the infection the consistency of the 

 quarter was the same as before inoculation. The milk 

 showed a normal appearance again and a lessened quan- 

 tity of sediment, which consisted of pus and a moderate 

 number of chains of cocci. 



Six days after infection this condition remained un- 

 changed. Upon cultivation of the sediment of the milk 

 on serum-gelatin-agar plates a moderate number of strep- 

 tococci but no staphylococci were found. 



Thirteen days after the inoculation the condition re- 

 mained unchanged and the animal was slaughtered. 



Autopsy. — The infected quarter was slightly swollen 

 and firm. The incision was juicy with milk. The lower 

 part of the cut surface was even and uniform, grayish- white 

 and yellow. The lobuli here present no milk points. Upon 

 pressure here and there small yellow fibrin cylinders were 

 expressed ( chronic streptomycosis ) . 



The virulence of the staphylococcus was obviously not 

 high and the infection did no more to favor drying of the 

 quarter than did the subsequent streptococcic sclerosis. 

 Therefore I only obtained a mild infection of the udder 

 which reached its height as a catarrhal inflammation in 

 four days. The chronic streptococcic infection was obvi- 

 ously favored by this short secondary infection. 



Udder-infection 



The pathogenic staphylococcus causes milk-infection 

 and acute stroma-infection. The milk-infection is the most 

 important. 



MILK-INFECTION [Parenchymatous ^lastitis] 



This is always primary and as a rule is caused by 

 infection through the teat canal, seldom by infection through 

 fresh wounds. 



