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 in trajugularly, 

 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 



