836 Diseases 0/ the Genital Organs 



sac, except of the two apical fetuses, is in contact at each 

 pole with the next fetal sac. The two apical embryonic sacs 

 end at the ovarian pole against the mouth of the oviduct, and 

 at the cervical pole, against the next embryonic sac. Since 

 the placentae are zonular, infection can not pass directly 

 along the uterine tube, but must pass between the fetal and 

 placental structures, destroying the life of the involved em- 

 bryo, or must pass through the embryonic sac and the con- 

 tained fluids and kill the embryo more directly. In either 

 case embryonic death would necessarily occur one after an- 

 other from the center of infection, and not en masse. If, 

 on the other hand, there is a specific infection which causes 

 abortion directly, either by passing from the blood stream 

 of the pregnant mother to the fetus and destroying its life, 

 by passing from the blood stream into the interplacental 

 areas of the uterus and thence through the chorion and am- 

 nion to destroy the embryo, or by forming bacterial products 

 anywhere within the animal body which are able to act di- 

 rectly upon the uterus and cause the expulsion of its con- 

 tents, then abortion en masse would occur in muciparous 

 animals such as swine and carnivora. But so far as I have 

 been able to observe in the abattoir or to learn from litera- 

 ture, the death of embryos occurs singly and seriatim from 

 one or more centers of infection. When all embryos have 

 perished, or the last to become involved are critically ill, the 

 uterus contracts and expels its contents. Otherwise, if 

 some embryos have not been mortally infected, they continue 

 their development and inhibit the expulsion of any fetal 

 cadavers present. When the living embryos have reached 

 maturity parturition occurs unless the outlet is blocked by 

 a macerating, emphysematous cadaver. Along with the 

 young which are born, there are expelled some or all of the 

 fetal cadavers, or their debris. If, however, an apical em- 

 bryo is dead and macerating, all others may be expelled and 

 (he cadaver remain in the diseased apex of the horn to pro- 

 duce a persistent pyometra. 



The prevention of the general infections of the genitalia 

 of carnivora has nol been sufficiently studied to permit the 



