Oct. 1,1925 
Abortion-Bacterin Treatment of Gows 
665 
serum was used because it was more satisfactory to read the aggluti¬ 
nation tests from it than from the milk. 
It was suspected that success or failure in infecting the guinea pigs 
might depend to some extent upon the quantity of milk the cows 
gave at the time the milk specimens were taken, or, in other words, 
upon the concentration of the bacteria; so a record was kept of the 
quantity of milk produced by each animal during the 24-hour period 
previous to the collection of the various samples. 
A practice was made of killing the inoculated guinea pigs in from 
five to eight weeks after the intra-abdominal injections. Serum-agar 
slants in nearly every case were sown with spleen tissue as a means 
of detecting Bact. abortus infection, and the cultures were subjected to 
incubation at 37° C. in closed jars in which 10 per cent of atmosphere 
was displaced by carbon-dioxide gas. 
Table II shows the quantity of milk produced by each of the 30 
cows during the 24-hour period just prior to the collection of the 
samples, the agglutination results with blood and milk sera, and 
outlines the procedure followed in inoculating, autopsying, and cul¬ 
turing the guinea pigs. 
The results obtained from the milk inoculations of guinea pigs 
f roved that 17 of the 30 cows carried Bact . abortus in their udders, 
t is probable that the number of carriers was considerably larger than 
was indicated by the inoculation results. The number oi guinea 
pigs used for each case was small, and death from enteritis, pneumonia, 
etc., was of frequent occurrence—factors which may have rendered the 
results somewhat misleading. 
Sixteen of the udder-infected cows were used for testing the value 
of the abortion-bacterin treatment. This number was divided equally 
into two groups. In order to make the division as nearly uniform 
as possible, an effort was made to include in each group animals 
which had been carriers for similar lengths of time as based on their 
histories and records of previous serological tests. 
The eight cows of one group (Nos. 51, 247, 409, 432, 435, 439, 442, 
and 468) were each given a subcutaneous injection of 10 c. c. of 
abortion bacterin on the following dates: May 24, May 29, June 3, 
June 9, June 15, and June 21 (1922). The bacterin was prepared 
from numerous strains of Bact. abortus which had been under arti¬ 
ficial cultivation for a year or longer. The organisms were killed 
by placing the flasks containing the suspensions in a water bath 
maintained at a temperature of 60° C. for one-half hour. The bac¬ 
terin consisted of approximately one billion organisms per cubic 
centimeter. The eight animals of the second group were used as 
controls. 
In order to determine whether there was any systematic disturbance 
resulting from such bacterin injections which might prove detrimental 
to the animals from the standpoint of production or otherwise, tem¬ 
peratures of the treated cows were taken on the days that the injec¬ 
tions were made and three times daily on the four following days. 
Their daily milk yield was also recorded. There was usually a slight 
reduction in milk-yield on the day following the treatment and some¬ 
times on the second day. A slight rise of temperature was observed 
in a few of the cows following the injections. In some of the animals 
there was as welling at the point of inoculation that did not entirely 
disappear for a week or ten days. 
