68 MASTITIS OF THE COW 



dry and in consequence of the chronic streptococcic infec- 

 tion presented less favorable conditions for the infection. 



Consequently, I obtained a severe udder-infection with 

 fever which was quickly eliminated by a catarrhal inflam- 

 mation in three days in consequence of the conditions 

 already named. The chronic streptococcic infection was 

 at first concealed by this secondary infection but later again 

 appeared and then became more severe. 



The similarity to the experiment with staphylococci is 

 apparent. 



Udder-infection 



The colon bacillus causes milk-infection and acute 

 stroma-infection. These infections manifest a great simi- 

 larity to those produced by staphylococci. 



MILK-INFECTION [Parenchymatous ^lastitisl 



This is the most important. It is always primary and 

 is caused by infection through the teat canal, seldom 

 through infection of a fresh wound. 



The local condition is usually confined to one quarter 

 but can involve more quarters by infection (for example, 

 during milking) . The primary lesion varies with the viru- 

 lence of the infectious organism and the condition of the 

 udder. A superficial or moderately deep necrosis is the 

 most common. A diffuse necrosis of the udder seldom 

 occurs. 



The quantity and quality of the inflammation varies 

 with that of the primary lesion. The inflammation can 

 be of a catarrhal or croupous nature. The infection shows 

 no tendency toward chronicity. 



Secondary infections may occur with strepto- and sta- 

 phylomycosis, as well as with pyobacillosis and tubercu- 

 losis. 



In this case the staphylomycosis can conceal the coli- 

 bacillosis while the others as a rule may become masked by 



