HEMOEEHAGIC SEPTICEMIAS AND PLAGUE 349 



and immunity against one is not necessarily potent against 

 another. An attempt has been made to use a polyvalent 

 serum, that is, one secured by injecting many strains of 

 organisms into the animal producing the serum, or by 

 mixing the serum secured from several animals immunized 

 each against several strains. In some cases the serum has 

 appeared to be effective in curing the disease in its early 

 stages. Bacterins, that is, killed cultures of this organism 

 have been quite extensively used in preventing the disease. 

 The disease, however, is sporadic and appears and disap- 

 pears with such suddenness that it is very difflcult to evalu- 

 ate the advantages of such treatment. 



The disease is particularly apt to appear among young 

 animals in first class condition. 



Pasteueella suiseptica 



Synonyms. — Bacillus suisepticus, Bacterium suicidum, 

 Loffler-ScTiutz bacillus and Bacillus suicida. 



This organism was usually described until recently as 

 the specific cause of the disease swine plague. In the early 

 history of the disease there was much confusion between 

 swine plague and hog cholera. The discovery that hog 

 cholera is caused by a filterable virus made necessary 

 critical examination of the disease swine plague. Undoubt- 

 edly in many instances, this organism is a secondary invader 

 in true hog cholera. However, there seems to be ample 

 evidence that there is a specific disease which may be known 

 as swine plague or swine septicemia caused by this organism 

 and distinct from hog cholera. 



Hemorrhagic Septicemias in Other Animals 



Bacteria belonging to the hemorrhagic septicemia group 

 have been found to cause diseases of this general type 

 among many animals other than those already enumerated. 

 Rabbit septicemia or rabbit plague is caused by Pasteurella 



