(UMBRA! LM, - I ."> 



it.' the attachment, and is !- resembling a cica 



It is destitute, of blo<>d \e>M-ls, whereas these, as well as uteirne 

 glands, are present in the remaining portion of ll.e OVBrgrOWing 

 mumus membrane. The blastula liis in tliis receptacle MOW, and 

 even into tin- beginning of the second month, loosely enclosed; after 

 opening the capsule the blastula can be removed easily ami \\ithout 

 injury. 



Whereas in othor Rfammals only thai cart f tin- uterine mii. 



membrane which contributes to the formation of the placenta is cast 

 (ill', in the case of Man there occurs a much more extensive ecdy>i> 

 of tin- most superficial Liver, nann-lv. <>\er the whole inner surf .-ice of 

 the uterine cavity. Here, too, the part which is ca-t off is designated 

 as deciduous membrane or decidua, and three regions arc di.-t inguish- 

 able (fig. 139) the part which is thrown around the l>]a>tnl 



"" reflexa (Dr), the part which forms tlio floor of the depression 

 in which the ovum has established itself as decidua serotina (Pu), and 

 the remaining { oiiion as decidua vera (Dv). 



In the reflexa we become acquainted with a structure which in 

 this complete form occurs only in the case of Man and the Apes, 

 whcrca- licinnnin^s of such a structure are also found in other 

 groups, as, e.g., in the Carnivores. Since the fn-tal capsule does not 

 at lirst completely fill the uterus, there remains between reflexa and 

 vera a space filled with mucu>. 



A second and in many respects astonishing result is, that e 

 in very youii^ and small blastodermic \e.-icle>, as all discoveries 

 agree in .showing, a well-developed ckorion with iilminlant cilli is 

 begun. 



The villi are either distributed over the whole surface of the ovum, 



or. :ts in PiKH'HKKT's Case (\\g. 140 A and B), they leave two opp 



poles of the blastula free. They attain a length of one millimetre, 

 and in part have the form of simple cylindrical elevations; in part 

 they already possess lateral branches. At no place have they fu>ed 

 with the decidua. Like the chorion itself, they consist of two layers 

 of a superficial epithelial layer, derived from the serosa, concern- 

 ing which AJII.FKLH and KoLLMANN have made very definite and 

 reliable statements, and of a layer of em'>ryonie gelatinous tissue, 

 which extends into the axis of the villi and already appears to hear 

 here and there blood- ves>, N. 



Unfortunately we have learned nothing from investigations of 

 these youngest of all human embryos concerning the structures 

 within the chorion, the remaining fotal membranes and the 



