Infections of the Ovum, Embryo and Fetus 519 



of domestic animals should, before it is accepted as proof, 

 be supplemented by a new and extensive series of experi- 

 ments with adequate control animals. Until this is done, 

 the controversy over the date of invasion of the infection 

 causing abortion can not be satisfactorily settled. 



I have held that there are two notable and important 

 dates of invasion — the intra-uterine infection of the fetus 

 and the time of coitus in adults. The latter has already been 

 consdered earlier in this chapter (I — Infections of the Geni- 

 tal Organs of Bulls). The first will be considered later (III 

 — The Congenital Infections of Calves). 



I. The Control of Abortion 



Under the views already expressed, abortion can not be 

 directly prevented or controlled, nor is there need for such 

 prevention or control. Being neither a disease nor a symp- 

 tom of any one infection, it demands no separate considera- 

 tion. It can be prevented only by the control of the infec- 

 tions within the genitalia of both sexes. These are consid- 

 ered elsewhere. 



When abortion came to be looked upon as a specific con- 

 tagious disease, veterinarians and cattle breeders hoped for 

 a definite remedy. Before it was believed that the cause of 

 abortion had been determined, Brauer (1889) thought he 

 had discovered a specific remedy in the subcutaneous injec- 

 tion of 2 per cent, carbolic acid to pregnant cows and heifers. 

 Highly favorable statistics were submitted by Brauer and 

 his followers in support of the new remedy. The researches 

 were without controls and very inaccurate. Apparently the 

 carbolic acid was given in herds where there had recently 

 been an "abortion storm," in which a notable decrease was 

 to be expected, or, as occurs frequently, a few animals had 

 aborted, all or nearly all of those which were in line to abort, 

 and then the remedy was given. Naturally there would be 

 no more abortions. But the career of the alleged cure was 

 short and it was soon found that if the utero-chorionic 

 space of a pregnant cow was highly infected and contained 



