398 Maximilian Herzog. 



The paper in which this statement was made shows a photomicro- 

 grajjh of these cells with karyokinetic figures. In re-examining the 

 photograph now, I find that these cells are comparatively small 

 cells. This would agree with the description of dividing decidual 

 cell as given by Marchand. 



The muscularis uteri, as far as it is included in the sections, 

 appears to consist of muscle fibers already somewhat hypertrophied. 

 Measurements by micrometer were not made. 



Summary. 



From the object described in the preceding pages, an ovum al- 

 most identical in size and type with the Peters' ovum, one may 

 draw the conclusion that these two ova represent the normal type 

 of the earliest known stage of human placentation. The mode of 

 placentation and implantation in both are practically alike. Cer- 

 tain retrogi'ade changes described in the cells and in the syncytium 

 of the Peters ovum must be looked upon as histopathologic changes, 

 probably due to the poisoning of the mother. This conclusion is 

 justified not only from our own case, but alike from the studies 

 of Marchand, Bonnet, Jung and others. 



If we now attempt a summary description of the ovum and its 

 manner of implantation and placentation, we have to make a few 

 hypothetical statements, but, on the whole, we can give a resume 

 based upon actual facts, as they are clearly represented by the speci- 

 men studied. 



A human ovum at the earliest stage of normal development 

 hitherto known, a stage which perhaps represents one to two weeks 

 after fertilization, is found interstitially embedded in the decidua. 

 It is incompletely separated from the cavity of the uterus, because 

 it is very superficially embedded and its outer pole is protected by 

 a thin, incomplete decidua capsularis or a coagulum only. The 

 ovum, after having been fertilized, has been transported to or near 

 to the place where it is found embedded. By the aid of an ecto- 

 dermal trophoblast shell, which probably secretes an enzyme de- 

 structive to the epithelial cells and the connective tissue of the 

 uterine mucosa, which is then in a premenstrual or menstrual 



