g6 Hemorrhagic Septicemia. 



which is potent against all the diseases of this group. The 

 vaccine is prepared from mixed cultures of the hemorrhagic 

 septicemia bacteria of sheep, cattle, dogs, horses, hogs and 

 chickens and attenuated at a temperature of 42-43° C. 



The vaccine prepared from the six varieties of virus is supposed to immunize 

 against all of the six diseases. Test animals inoculated with this vaccine will 

 show a resistance against a virulent infection, while control animals will die or 

 become severely affected (with the exception of very virulent intravenous infections). 

 In practice the vaccinations are supposed to have given good results, especially 

 against the acute septicemic forms of hemorrhagic septicemia, as for instance against 

 chicken cholera and hemorrhagic septicemia of sheep. On the other hand, the re- 

 sults in the slower forms which are frequently associated with mixed infections 

 were less favorable, although even in these cases the mortality has been supposedly 

 reduced from 50% to 12%. 



The immunization consists in a subcutaneous or intraperitoneal injection of 

 the vaccine; the second inoculation follows in from 12 to 15 days. In infected 

 localities it is advisable to undertake the vaccination on sucking animals 8 to 10 days 

 after their birth, or at least shortly before weaning. The immunity produced by the 

 vaccination lasts for about a year, and therefore it is advisable in infected localities 

 to repeat it annually. 



Serum Immunization, Kitt (1897) found that animals 

 (among others, horses and cows) which have been injected 

 with the virus of chicken cholera produce a (blood serum which 

 protects chickens against an artificial infection of virulent 

 material. This fact was later confirmed in connection with 

 swine plague by Schweinitz and Leclainche while Lignieres & 

 Spitz (1902) showed that this principle applies to all diseases 

 of the hemorrhagic septicemia group. 



With regard to the immune sera, there exists a similar 

 reciprocity as in the case in which the vaccines are prepared 

 from living cultures. Kitt & Mayr have established these facts 

 for swine plague and fowl cholera, Grosso for hemorrhagic sep- 

 ticemia of cattle, fowl cholera and swine plague, while Lignieres 

 generalized the principle. Accordingly an immune serum pre- 

 pared from certain varieties of the bipolar bacillus protects, in 

 the first place, against a virulent infection caused by the respec- 

 tive varieties. However, it is also protective, although in a 

 lesser degree, against the other related varieties. Blood serum 

 of' animals which have been hyperimmunized with different 

 varieties of the bipolar bacillus has likewise a protective action 

 against all the ■'^■arieties which were used in the preparation of 

 the serum. 



Based on these experimental observations Lignieres & Spitz pre- 

 pared a so-called polyvalent immune serum against all the pasteurellosEe. 

 The serum is prepared by inoculating peptone bouillon with the above 

 mentioned six varieties of the bipolar bacillus, and with the mixed 

 cultures prepared in this manner horses are at first subcutaneously, 

 later intravenously injected with increasing quantities (5 to 20 cc). 

 Horses highly immunized in this way produce a serum which affords 

 protection against all of the diseases of this group, and it even possesses 

 a curative action to a certain degree if employed in the early stages of 

 the disease. Similar results were also obtained by Klepzoff, while Broil 



