rai II:IM. MI.V ur, 



T! ... '.,-, nibticmoe </ (/ choriom 



with Mellate :ini spindle-shaped cells in tin- liuier branches ; r 

 larger stems it takes on a more fibril la r eondit in. 



The views of investigators are still at variance upon tin- imp. >i 

 point whether the epithelium of t/i>: niembran<i 6&OTM (md (! ///// is 

 of foetal or maternal origin. KOI.UKKU, LAN.II\NS, LEOPOLD, and 

 others derive it from the cells of the serosa, whereas KKI<>I,\M 

 Ti KNKK, whom BALFOUR has followed in his text-book, Mate, more 

 or less explicitly tliat, although originally the cells of the M 

 cover the villi as an epithelium, during the mutual int.T-mwth of 

 the placenta fostalis and the placenta uterina they peri.-h. an<l are 

 replaced by proliferating cells of the decidua serotina. 



The recent investigations of KASTSCHENKO and SEDGWICK MIN^I, 

 as well as the observations of WALDEYER, KUPFI I.K. CKAF SIM :i:, 

 and KEIBKI,. all'ord much enlightenment on this controv 

 suhject. 



K ANTM IIKNKO, who has most carefully investigated tin- epitlr. limn 

 of the chorion frondosuui in the different months of preir nancy, 

 and with whom recently S. MINOT essentially agrees, can readily 

 distinguish two layers: (1) a cell-layer (LANGHANS), which 

 immediately upon the gelatinous substance of the villi and the 

 connective-tissue membrana chorii, and in which the limits of some 

 of the cell-territories may be made out, and (2) a multinuclear 

 protoplasmic layer, in which separate cells cannot be demonstrated 

 in any manner. These layers are rather sharply coutiaMed from 

 each other. 



The double layered chorionic epithelium is already distinctly 



nt in eggs four weeks old, as is conJirmed by KLPFKER, GRAF 



SPEE, and KEIBEL. The deeper layer con-i^ts of a single sheet of 



well-marked cubical cells; the outer layer discloses at the free surface 



a striated border, the significance of which is obscure. 



In the following months the chorionic epithelium undergoes note- 

 worthy alterations. The deeper layer becomes thickened in n. 

 places intosperial cell-patrhe>, in which the elements are much super- 

 posed. The outer, protoplasmic layer changes still more; it is 

 converted into a hyaline, peculiarly lustrous Miltanre, which i-> 

 traversed by numerous fisMiiv> and sj ares, and has therefore received 

 from LANGHANS the name "canalised fibrin. 



There is one conclusion that in my opinion results from the>e in\e>- 

 tigations: the view of TURNER, according to which the chorionic 

 epithelium is replaced in the course of pregnancy by uterine 



