UDDER-STREPTOMYCOSIS 47 



for the infectious organisms present. Only the number 

 of cells is slightly increased, due to the low grade inflamma- 

 tion. In consequence of this the organisms multiply, enter 

 new tubules and lobuli, extending the inflanmiation and 

 from here they can spread the condition further upward 

 and outward (typical chronic streptomycosis). 



A secondary infection frequently occurs. Colon bacilli 

 and staphylococci may complicate the condition. Tuber- 

 culosis and pyobacillosis may also be induced, although 

 pyobacillosis is the most common secondary infection. 



In these secondary infections the new infection may 

 conceal the primary infection with its own individual and 

 aggressive character. 



A saprophytic invasion of an original streptococcic 

 infection is infrequent and only occurs in those of the high- 

 est streptococcic virulence when the cell resistance has been 

 lowered. 



GENERAL CONDITIONS 



Blood infection can occur and manifest itself clinically 

 by multiple arthritis, which is common in the hock joint. 

 Fever can be more or less severe or be absent, depending 

 upon the virulence of the organism and the condition of 

 the udder. It is diminished by the inflammation so that 

 the animal is free from fever after a few days, as a rule. 

 Fever is seldom fatal. 



In saprophytic invasion with gangrene, fever becomes 

 chronic and death may occur. 



Termination. — The condition is seldom fatal. As a 

 rule it runs a course of from a few days to months and 

 years to recovery. The udder usually heals with difl*use 

 sclerosis and parenchymatous atrophy, which conditions are 

 most severe following gangrene. 



Clinical Symptoms. — ^We discriminate here between 

 the acute and chronic condition. 



The course of the acute condition varies from a few 



