50 THE EMBEDDING OF THE OVUM. 



uterine epithelium and surely one or the other gland would be 

 found opening into the ovum." 



I agree, that an ovule in this way might enter such a furrow 

 and be caught, but still it could there sink into the mucosa, but 

 even if it should further develop while wedged in this groove, 

 I cannot see the necessity that it should remain surrounded by 

 uterine epithelium and that as Peters explains this protecting 

 maternal layer should then be secondarily destroyed by the pro- 

 liferation of the fetal trophoblast. 



In the premenstrual stage the epithelium of the uterine mu- 

 cosa is loosened, swollen and rendered detachable by small sub- 

 epithelial hemorrhages to such an extent that an intact, firmly 

 adherent and continuous epithelial covering in such a furrow 

 could not be expected and hardly ever is found. Therefore, 

 from an anatomic histologic point of view, I cannot object 

 against the possibility of ovular implantation in a furrow and 

 would not regard it as surprising if a gland would run up to the 

 ovular chamber (compare Fig. 24 dr t Plate XIV) and appar- 

 ently open into it. Such facts do not alter my present assump- 

 tion that the ovum passing through the superficial epithelium and 

 pushing the glands aside, burrows itself into the mucosa. 



In my opinion, it matters not where the ovum has become 

 attached and where embedded, whether on the summit of a 

 cotyledon (as in 'Peters' case) or near the slope of an elevation, as 

 in my specimen, or in a furrow, the ovule will everywhere be 

 the source of considerable irritation and a pronounced reaction in 

 the adjoining tissues. This reaction has been so well described 

 by Peters that I give my own opinion by simply citing his own 

 words (pg. 29) : "One seems justified in assuming that at the 

 site of implantation, either through mechanical irritation or by a 

 provision of nature, the tissues become highly congested, plasma 

 (edema) and corpuscular elements of the blood extravasate, the 

 preformed endothelial tubules dilate, the mucosa swells and 

 thickens. It still remains undecided in which manner the blood 

 elements are set free, whether as a result of an increased pres- 

 sure within the vessel or through rhexis or a free diapedesis, or 

 possibly the capillary vessels have been opened by the epiblast, 

 which has begun to proliferate as soon as it came in contact with 

 the maternal tissues. The fact that the fibrinous plug which lies 

 on the summit of the ovum pointing into the uterine lumen, con- 

 sists of blood elements, almost forces us to assume that during 

 the process of the embedding of the ovum into the edematous 

 connective tissue stroma, the ovum, and its free surface towards 

 the uterine cavity, is surmounted by a blood coagulum which pro- 



