382 Maximilian Herzog. 



the tropboblast is last seen, we likewise have evidences of its 

 great destructive tendencies. The next sections show numerous 

 degenerating, dropped-off decidual cells, mixed with blood. Thus, 

 there is formed here also a kind of cavity filled with blood and 

 detritus. However, it does not reach the surface, but remains sep- 

 arated from it by decidual tissue. We see the ovum then every- 

 where more or less surrounded by cystic blood spaces or free blood. 

 In this respect the early human ovum is very much like that of 

 the hedgehog and mouse, as described by Hubrecht and Bonnet, 

 surrounded on all sides by maternal blood, floating as it were in a 

 lake of blood. The conditions in our ovum are more or less identical 

 with what had been found by Peters in his case. 



It can be seen in Fig. 25 that the embryonic shield is anchored 

 by its allantois to the chorion mesoderm near the inner pole of the 

 ovum and farthest away from the outer pole and the thin capsu- 

 laris. The position of the embryo with reference to its outer and 

 inner poles is thus identical with that of Peters' ovum. In the 

 Jung ovum likewise the embryonic shield appears to hold the same 

 relations to the maternal organism, through orientation in this last- 

 mentioned specimen, which was not obtained in situ, but by curette- 

 ment, is not absolutely certain. The apparently identical position 

 of the embryonic shield in the three young human ova is very prob- 

 ably not at all a matter of chance or accident, but is due to a very 

 early automatic orientation of the ovum for the benefit of the 

 developing embryonic shield — from a biogenetic standpoint the 

 most important part of the ovum. 



Examining the sections which show the beginning and the course 

 of the canal, the following conditions can be ascertained : The 

 entrance of the canal is evidently not in a gland duct, but in an 

 interglandular septum, through a decidua which here, in spite of 

 profound degenerative processes, shows well the character of a 

 compacta. On both sides of the entering canal we see the enlarged 

 tortuous necks of uterine glands. Enormously enlarged capillaries 

 reaching from the sides of the entering canal to the very surface can 

 also be seen. Both at its entrance and along its course the canal is sur- 

 rounded by enlarged gland spaces. The glandular epithelium every- 



