Puerperal Diseases of the Uterus 565 



ble in the sow, where the fetal cadavers are common in the 

 uterus and their expulsion inhibited by the presence of liv- 

 ing embryos. In each of these conditions the placentitis 

 completes its course, at least up to the point of detachment 

 of the fetal from the maternal placentae, or the cotyledons 

 become necrotic and separate from the uterus. Conse- 

 quently if the cadaver is finally expelled, the fetal mem- 

 branes do not remain behind in the uterus. Accordingly 

 when retained fetal envelopes occur, the stage of their de- 

 velopment varies widely in different cases. In abortion oc- 

 curring late in pregnancy the placentitis may be far ad- 

 vanced, so that the fetal membranes are expelled with the 

 fetal cadaver, or, detained after the expulsion of the cada- 

 ver, may come away in a few hours, days or weeks. 



If a cow calves and the fetal membranes are retained, the 

 stage of the placentitis may be partly gauged by the health 

 of the calf. If the calf is feeble and dull, showing severe 

 sepsis, the placentitis is probably far advanced and the 

 course of retention nearing completion. If the calf seems 

 well but breaks down within a few days with dysentery, it 

 indicates, with certain limitations, that the placentitis was 

 moderately advanced at the time of birth and that the re- 

 tention of the membranes will probably continue for the 

 maximum duration. On the other hand, if placental reten- 

 tion follows the birth of a quite vigorous calf, the placentitis 

 is certainly in its first stages and probably involves materi- 

 ally only a few of the cotyledons located at the cervical end 

 of the uterus, while the cotyledons at the ovarian end are 

 healthy. Then the dehiscence of the membranes at the 

 ovarian end of the uterus may occur at once and these 

 drag upon the areas of detention, mechanically detaching 

 the feebly retained portions. Slight retention of the fetal 

 membranes at the cervical end of the uterus plays an im- 

 portant part in the phenomenon of their final expulsion. 

 Ideally it might be expected that the fetal membranes would 

 be expelled with the placental surface of the chorion on the 

 outer side, but in a majority of instances the dehiscence oc- 

 curs first at the ovarian end of the uterus, the detached por- 



