vi PEEGNANCY PAETUEITION PUEEPEEIUM 215 



of perforation the epithelium was wanting, and there was in its 

 place a sort of plug formed by a fibre-sanguineous network. The 

 ovum showed an outline of the embryo like that found by 

 Eeichert and a chorion provided with villosities. The mucous 

 membrane round the chorion" showed dilated capillary vessels 

 among the villi (Fig. 79). 



The excavation in which the ovum had settled was clearly the 

 result of a process of softening of the mucosa and cytolysis of the 

 sub-epithelial connective tissue. Is this due to the irritative and 

 cytolytic action of the growing epithelial cells of the chorion, so 

 that we can affirm with Sharpey and Bumm that it is the ovum 

 in process of development which hollows out its own bed in the 

 thickness of the uterine mucosa ? This does not seem probable, 

 for even if we admit the theory, it is not easy to explain why the 

 non-fecundated ovum is not capable of acting in the same way on 



FIG. 78. Ovum found by Reichart in the uterus of a woman who had committed suicide. 

 Magnified to four times natural size. (Front and side view.) 



the uterine mucosa, and the researches of Frankel and Kohn have 

 proved that the grafting of the fertilised ovum in the uterus and 

 its further development are due to the internal secretion of the 

 cells of the corpora lutea. Sfameni (1904) definitely states that 

 the ovum in process of attachment does not exercise any de- 

 structive action on the uterine mucosa, but merely stimulates it 

 to proliferate ; this results in the wrapping of the ovum in a fold 

 of maternal tissue, called the decidua. The most recent researches 

 of Leo Loeb (1910) have proved on the other hand that when the 

 uterine mucosa has been made sensitive by the internal secretion 

 of the lutein cells, the simple mechanical action of the ovum is 

 sufficient to set in motion the whole process through which the 

 formation of the decidua, the attachment of the ovum, and the 

 constitution of the placenta are brought about. He succeeded 

 indeed in producing these processes artificially in the uterus by 

 inserting in it chemically inert foreign bodies, thin capillary glass 

 tubes, for instance, introduced through the cervix. 



II. In the preceding chapter, when treating of the relations 

 between ovulation and menstruation, we mentioned the changes 



