GRANULAR VENEREAL DISEASE AND ABORTION IN CATTLE. 21 
cow with abortion bacilli will tend to cause abortion about the two 
hundredth day of pregnancy, the organism tempering its rapidity of 
action according to the exigencies of the case. 
If in Table 3 we let X equal the number of days elapsing after 
impregnation until inoculation is made and Y equal the number of 
days elapsing between inoculation and abortion, then X + Y = about 
200 days, although the values of X and Y may each vary inversely 
from 1 to 200. 
4. The alleged cases of experimental abortion recorded by the 
different investigators present very grave questions in relation to the 
avenue or avenues of infection. These we discuss later in a separate 
chapter. 
There is, it is true, much laboratory evidence tending to show that 
the introduction of the bacillus abortus intravenously, hypodermi- 
cally, per vaginam or orem, may lead to the invasion of the utero- 
chorionic cavity and cause the death and expulsion of the fetus, but 
as yet no reliable means have been devised for determining that the 
same organisms did not exist already within the utero-chorionic space. 
Apparently a very high percentage of the experimental heifers and 
cows inoculated have aborted, but this is merely comparative, not 
positive. 
In the experiments of the British Royal Commission, of 5 heifers 
inoculated subcutem, 1 aborted; of 9 heifers inoculated intrajugularly, 
4 aborted; of 5 heifers inoculated per orem, 1 aborted; of 9 heifers 
inoculated per vaginam, 1 aborted; making a total of 28 heifers 
inoculated, of which 7, or 25 per cent, aborted. 
This rate of abortion does not greatly exceed the prevailing rate of 
abortions in first pregnancies. However, the commission determined, 
by autopsy or otherwise, that 11 additional heifers were infected and 
might have aborted, which makes a total of 18, or 64 per cent, of 
their experimental heifers that were infected. It is not at all rare 
for more than 64 per cent of heifers to abort from natural infection. 
In each case we have found recorded of abortion, in cattle in which 
an early autopsy has been performed, there has been found in the 
utero-chorionic space a peculiar exudate which has not been recorded 
as occurring in other organs or in the uterus of other animals than the 
cow, and in which the abortion bacilli are usually, if not always, 
found. 
As with the abortion bacillus, so with the granular venereal disease; 
there are no adequate control observations. Under the conditions 
shown in Tables 1 and 2, no herds free from the granular venereal 
disease can be found, and hence we can not say that, without that 
malady, contagious abortion could or could not exist. 
It is a notable clinical fact, however, that those herds abort most 
in which the granular venereal disease is most intense. When a large 
