A rtificial A bortion 1 47 



power to cause contraction of the uterus with the expulsion 

 of its contents. 



Many veterinarians and research workers with the B. 

 abortus of Bang believed for some years that this organism 

 had the power to act directly as an abortifacient. Professor 

 Bang made no such claim, so far as I have found, but in- 

 stead contended that the abortion was the result of an endo- 

 metritis for which he believed the B. abortus responsible. 

 If the B. abortus could cause abortion by directly acting 

 upon the central nervous system, it should be able to do so 

 when the bacillus is multiplying elsewhere than in the 

 uterus or fetus, but in all cases, when the aborter is promptly 

 destroyed, metritis is present and bacteria are recognized 

 as the cause of the metritis. Hence, so far as known, abor- 

 tion can not be caused artificially by means of toxins or 

 other bacterial poisons. 



Artificial abortion is quite certainly induced by breaking 

 down the uterine seal, invading the uterus, and douching 

 the cavity. The earliest date after copulation at which abor- 

 tion can be induced by uterine douching is undetermined. 

 Douching the uterus with a disinfectant immediately after 

 copulation is quite certain to destroy all spermatozoa and 

 prevent fertilization, but after the lapse of a brief time, 

 certainly less than an hour in the cow, the spermatozoa, 

 having passed into the oviducts, are beyond reach. Mar- 

 shall, citing Hensen, states that in the rabbit the spermato- 

 zoa travel from the vagina to the ovary in from fifteen min- 

 utes to two hours. If that be correct, it is well-nigh im- 

 possible to douche the uterus early enough after copula- 

 tion to prevent fertilization. Marshall states that the fer- 

 tilized ovum of the rabbit enters the uterus at about three 

 days after fertilization. During this interval uterine 

 douching can not interrupt pregnancy. In the larger domes- 

 tic animals, the migration of the fertilized ovum from the 

 pavilion of the oviduct into the uterus is believed to be 

 slower than in the rabbit. Marshall (') gives the duration 

 of migration in the dog as eight to ten days. During this 



1 Marshall, A. Milnes, Vertebrate Embryology, 1893, p. 471. 



