Infections of the Ovum, Embryo and Fetus 477 



often, but the newly fertilized egg has little, if any, more 

 power of resistance than the spermatozoon and unfertilized 

 ovum each possessed prior to their union. It is an indisput- 

 able clinical fact that salpingitis generally prevents recog- 

 nizable pregnancy. This renders it reasonably clear that 

 the infection in the oviducts or uterus kills the spermato- 

 zoon or ovum. The recognizable destruction of the embryo 

 or fetus is so common that the unseen death of its earliest 

 stages must also be frequent. Any infection capable of 

 causing the death of an embryo or fetus must logically be 

 more readily able to cause death of the far less resistant 

 organism. Thus a heifer is bred possibly eight to ten or 

 more times at regular or irregular intervals. Sometimes 

 she may appear pregnant for one to two or more months. 

 Finally she recognizably conceives and pregnancy contin- 

 ues one hundred to two hundred or more days, when she is 

 observed to expel a fetal cadaver. One death of a fertilized 

 egg has been observed, while many deaths during the earlier 

 periods have passed unseen. The deaths of the spermatozoa 

 and of the unfertilized or fertilized ovum are far more nu- 

 merous and cause infinitely greater economic losses than do 

 abortions. In many valuable herds of pedigreed cattle, an 

 average of three copulations is necessary for each recog- 

 nizable pregnancy : there is an initial failure in 67 per cent, 

 of attempts at reproduction. 



The farce of curing the disease or preventing the death 

 of the ovum, spermatozoon, or fertilized egg by measures 

 taken after coitus, as is so common with abortion, has not 

 become established. The avoidance of such death clearly 

 lies in the fundamental principle that the physiologic re- 

 production of young rests upon the sexual contact of two 

 healthy individuals. 



B. Death of the Embryo with Persistence of the 

 Embryonic Sac. Cystic Mole 



As soon as the embryo has formed and its sac has ac- 

 quired recognizable dimensions, embryonic death may be 

 clinically observed if accurate attention is given at the criti- 



