STUDIES OF IMMUNITY AGAINST HEMOR- 
RHAGIC SEPTICEMIA 
L. VAN E3 AND H. M. MARTIN 
Department of Animal Pathology and Hygiene 
Within recent years a considerable interest has been de- 
veloped in the part played by Bacillus bipolaris septicus in the 
production of disease among farm live stock. Hemorrhagic sep- 
ticemia was and is yet represented to be a prolific source of loss 
among the domesticated mammals. So far as our own observa- 
tions pertaining to Nebraska live stock are concerned, there does 
not seem to be cause to attach great importance to this disease 
as a menace to cattle, sheep, and swine. In our investigations 
we very rarely encountered this infection, in spite of considera- 
ble effort to do so and in spite of an abundance of suspected 
material from cattle, sheep, and swine. 
In only one direction can we recognize the organism as a 
serious source of loss, and that is in connection with fowl 
cholera, a disease which exacts a heavy annual toll from our 
poultry raisers. 
It is this last named disease above all which gives warrant 
for a study of the immunology of hemorrhagic septicemia in 
general. 
As one of the phases of our inquiry an effort was made to 
acquire some general knowledge regarding the immunizing value 
(1) of sera prepared with the aid of Bacillus bipolaris septicus 
procured from cattle and swine or (2) of those alleged to be of 
service in the control or treatment of hemorrhagic septicemia in 
the species mentioned. The experiments reported in this publi- 
cation were almost exclusively made with sera purchased from 
dealers in biologic products. 
The sera examined were prepared by means of strains of 
Bacillus bipolaris septicus obtained from cattle and swine or 
which were represented, at least, to be useful in the management 
of hemorrhagic septicemia in the species named. 
In the test of the sera (1) represented to be useful in the 
control of the disease in cattle or (2) which were prepared by 
means of a cattle strain of the Bacillus bipolaris septicus, use 
was made of cultures of our cattle strain Xo. 020, while in 
