518 Diseases of the Genital Orga?is 



H. The Date of Invasion 



The infection which causes abortion invades the uterus 

 prior to the establishment of the uterine seal. The ortho- 

 dox believers in a specific contagious abortion have stoutly 

 contended that the infection commonly invades the uterus, 

 fetal membranes and fetus after pregnancy has become es- 

 tablished, the placenta has formed and the cervical canal 

 has become hermetically sealed. As already related, they 

 have attempted to prove, and believe they have proven 

 their contention by experimentally causing abortion in an 

 existing pregnancy. In the cow, as discussed in preceding 

 pages, the experimenters have kept no checks or controls 

 and their experimental inoculations have been followed by 

 no higher rate of abortion than is commonly observed in 

 uninoculated animals. They have further attempted to 

 prove that a pregnancy already established can be inter- 

 rupted by artificial infection of pregnant animals of other 

 species. But, as with cows, no control animals have been 

 kept. The rate of abortion following inoculation has not 

 been remarkably higher than common in the species used, 

 and there is no evidence that an equally high ratio of abor- 

 tion would not have followed the injection of a sterile, inoc- 

 cuous substance. It is a perfectly well known clinical fact 

 that the various species of domestic animals commonly co- 

 habit on farms. Horses, cattle, swine, dogs and cats are 

 in intimate contact, but cohabitation fails utterly to cause 

 the spread of abortion from one species to another. If 

 abortion were spread by the means alleged by the believers 

 in "contagious abortion" such as the eating by pregnant 

 animals of food which has become contaminated by the dis- 

 charges from an aborter, by the infection carried upon the 

 boots, hands and so forth of attendants, or by the mere 

 presence of an abortion, an abort, or the afterbirth of an 

 abort in a stable or a field, an outbreak of abortion in one 

 species would be the signal for many pregnant animals of 

 whatever species to abort. The recorded evidence of the 

 transmission of "contagious abortion" of cows to all species 



