4 Nebraska Experiment Station Research Bulletin 17 
In nearly all the cases, the vaccines or bacterins were pur- 
chased directly from the manufacturer, selecting those especially 
which were most conspicuously advertised. The degree of im- 
munity produced by them was always tested by the use of B. 
bipolaris cultures or material primarily obtained from the same 
species as the one upon which the bacterin or vaccine was sup- 
posed to confer protection. In one instance we were even for- 
tunate enough to test the immunity of our test animals against 
the very strain of B. bipolaris found in the preparation. 
In the matter of dosage, we have with but few exceptions 
selected the one recommended on the label. In some cases we 
used smaller, in others larger doses in order to ascertain a pos- 
sible influence upon immunity by such variations. 
In only a few instances did the vaccine or bacterin injec- 
tions produce any immediate unfavorable effect on the test 
rabbits. In most of those cases there was indisposition or even 
sudden deaths immediately following the injection and this we 
could attribute entirely to the presence of preservative agents 
With those few exceptions we encountered no trouble caused by 
the relative large doses. 
Sample No. 113. 
The first preparation which we had occasion to give a trial 
was one sold as a “Mixed Infection Bacterin." This name, at 
first sight, made it appear that it would perhaps be unwise to 
expect an immunity against hemorrhagic septicemia from its 
use. However, in accompanying printed matter the manufacturer 
assured us that it contained forty-live per cent of B. suisepticus. 
and because of the further statement that “Each two mill contains 
the most satisfactory combinations of organisms and in amounts 
sufficient to insure immunity against each possible infection," 
we considered ourselves justified in using this bacterin in our 
tests. In passing it may be of interest to observe that according 
to the manufacturer's claims it should cause immunity against 
four other bacterial species aside from hemorrhagic septicemia. 
To what extent any claims in regard to the latter disease 
are sustained by our experiments may be seen from Table I. 
