PLACENTA. 187 



to the most vascular part of the uterus, make an assertion that is 

 void of sense; for, admitting that the ovule is at first entirely con- 

 cealed in the centre of the decidua, as several authors have stated, 

 and still continue to assert, who is to tell the villi that the womb is 

 more favorably disposed for their reception in one place than in 

 another? Since observation proves that the vdli at first cover the 

 whole vesicle, instead of growing on one portion of it, why should 

 not the placenta occupy more or less regularly the whole superficies 

 of the ovum instead of covering only one-fifth of it? 



Had Osiander, Stein, and some other writers, reflected more care- 

 fully upon the subject, they doubdess would not have advanced the 

 opinion that the point of insertion of the placenta depends upon the 

 specific weight of the fecundated ovum, and consequendy, on the atti- 

 tude assumed by the woman immediately after impregnation. Indeed, 

 two remarks suffice to overthrow this system: 1. As the vivified 

 ovule does not leave the tube for eight days, it is manifest that until 

 then, the attitude of the woman is a matter of indifference as to the 

 point in question; 2. Be the time what it may that is considered 

 necessary for the germ to pass from the ovary to the womb, it is 

 clear that it will find the woman on foot more frequently than in any 

 other posture, and if the idea of Osiander were correct, that the im- 

 plantation of the placenta over the cervix, instead of being very rare, 

 ought on the contrary to be the commonest of all. 



483. I think I have discovered a much more natural explanation 

 of this phenomenon, and shall venture to submit it to the examina- 

 tion of naturalists; upon entering the womb, the ovule necessarily 

 meets with the anhistous sac, and can proceed no farther without 

 detaching it; now, if the adhesion of this sac is the same throughout, 

 the vesicle follows its original direction, glides along the fundus of 

 the womb, which, with the assistance of the decidua, seems to pro- 

 long the channel of the tube to that of the opposite one, or else it 

 stops as soon as it issues from the tube, and then the placenta at- 

 taches itself to one of the angles of the uterus. If the adhesion is 

 stronger above than it is below, we may conceive that the ovum will 

 descend more or less towards the cervix; if the adhesion be strongest 

 in front, it will be directed backwards, and so of the other points. 

 This hypothesis is further confirmed by direct observation; of thirty- 

 four women who died while pregnant, or soon after delivery, at the 

 Hospital de Perfectionnement, 1 found upon examining tlie parts, that 

 the centre of the placenta corresponded to the orifice of the tube in 

 twenty cases, it was in front of it in three cases, behind it in two, 

 below it in three, and in six cases only, towards the front of the 

 uterus. 



