Embryonic Development in Man. 397 



aware that llie specimen described is one obtained post-mortem. 

 Howc\er, the rapid cooling on ice and the subsequent proper fixa- 

 tion had well preserved it. This, among other things, is attested 

 to by the fact that mitotic figures were found in the embryonic shield 

 and in the trophoblast. 



None of the decidual cells, either large or small, show any karyo- 

 kinetic figures. 



Jung, who describes mitoses in the decidua of his specimen on 

 page 29 of his monograph, says : ''Marchand and Bonnet are the 

 only authors who have heretofore described mitoses in the decidua. 

 The present author in a paper published in July, 1898 (Super- 

 fetation in the Human Eace), described among others an aborted 

 specimen of suiierfetation. Both embryos were contained in the 

 intact fetal membranes. One embryo was 8.6 cm. long; the other 

 16.5 mm. The superfetation was proven by a microscopic examina- 

 tion of the embryos and of their placenta?, showing in both the 

 different stages of development. In the description of the placenta- 

 tion of the small ovum the following passage occurs: "Large ap- 

 ])arent islands of decidual cells! In some places the decidual cells 

 present a very beautiful feature which I had not observed before 

 in the deciduse of many other placentae examined. As is well- 

 known, the large vesicular, round or oval nuclei of decidual cells 

 are, as a rule, quite poor in chromatin, which is distributed in the 

 form of small granules in a peripheral manner near the nuclear 

 niend)rane. In some places of the young placenta of this case 

 the nuclei are rich in chromatin, consistiup- of coarse granules and 

 masses, arranged in an aster-shaped manner, occasionally a disaster 

 is fairly well recognizable. We have to deal with karyokinetic 

 figures. That this is really the case, and that we are not dealing 

 with a degenerative process of the nuclear chromatin is proven by 

 the fact that the aster stage can be well recognized, and, secondly, 

 by the observation that leucocytes are absent at the place where 

 the karyokinetic figures in decidual cells are found. I have pre- 

 viously pointed out that where a degenerative process — coagulation 

 necrosis — is going on in the decidua we find great numbers of poly- 

 nuclear leucocytes, many of which show nuclear fragmentation." 



