SEPTICEMIA HEMOEEHAGICA 81 



to which the introduction could be traced. In such 

 cases the outbreaks can be explained by a sudden 

 increase in the virulence of the bacteria which are 

 present in the soil or in the healthy animal, favoured 

 by a decreased resistance of the animal body to 

 infection. 



The chief diseases resulting from infection with 

 the bipolar bacteria which occur in the British Isles 

 are hemorrhagic septicemia of cattle, fowl cholera, 

 and swine plague. A bipolar bacillus, the B. sui- 

 septiciis, is a very common secondary invader in 

 swine fever. It is this organism that is also respon- 

 sible for swine plague. Septicemia hemorrhagica is a 

 common disease in this country. Personally, I have 

 experienced several outbreaks, all of which occurred 

 in the summer, and especially when the drinking 

 water was low. I believe that many of the outbreaks 

 of so-called bracken poisoning are in reality outbreaks 

 of this disease. Clinically the symptoms of septicemia 

 are practically the same as those described for 

 bracken poisoning. 



Etiology. — B. {hipolaris) hovisepticus. 



Pnqiliylaxis. — As the disease in cattle is generally 

 very acute, animals often die within twelve hours of the 

 appearance of symptoms ; therefore it is evident that 

 prophylaxis is the better course to adopt. At the 

 present time there are three methods of vaccination 

 in vogue : 



1. Vaccination with dead cultures, or *'bacterins," as 



they are now commonly called. 



6 



