748 Diseases of the Genital Organs 



and that consequently it causes abortion in other animals 

 which it may invade. Having carved out the idol of specific 

 contagious abortion in cattle, it becomes obligatory upon the 

 part of those who thus believe to have a specific contagious 

 abortion for each species of mammal in order to account for 

 intra-uterine death which overtakes and destroys a large 

 proportion of embryos in every land and in all species of 

 mammalia. Perhaps no animal furnishes more direct evi- 

 dence of the non-existence of a specific infection with a di- 

 rect abortifacient action than the sow. One embryo or five 

 or six embryos in the uterus of the sow may succumb to in- 

 fection present, but the infection is impotent to cause the 

 expulsion of the cadaver or cadavers so long as a healthy 

 immature fetus remains. If, however, all embryos die or 

 become seriously ill, the endometrium is generally involved 

 and the diseased organ revolts and expels its perilous con- 

 tents. Otherwise the orderly completion of pregnancy pro- 

 ceeds, and at full term the living fetuses are born and the 

 cadavers are expelled. The uterus accordingly evacuates its 

 contents in two ways — the ordinary physiologic birth when 

 the fruit is ripe, and the pathologic expulsion of its con- 

 tents when the embryo or embryos and their coverings are 

 dead or seriously diseased, associated with concurrent dis- 

 ease of the endometrium identical in cause. Any organism 

 capable of causing endometritis and placentitis with death 

 or critical illness of the intra-uterine young may and does 

 lead to abortion, but no microorganism is yet known which 

 can directly and specifically cause uterine contractions. 



The B. abortus is a common resident of the genital tract 

 of sows which abort or are sterile. It is common in boars. 

 It is not known to be uncommon in healthy swine. Its com- 

 mon presence where abortion and sterility prevail justifies 

 the belief that it is one of the bacteria which serve to inter- 

 fere with reproduction. But there are other organisms pres- 

 ent, along with the />'. abortus, which have not been studied 

 and the significance of which can not now be guessed. 



The control of the genital infections of swine is to lie at- 

 tained by the adaptation and application of the principles al- 



