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never inclosed embryonic blood-vessels, but sometimes some con- 

 nective tissue of the allantois entering the ectoplacental cone together 

 with the large blood-vessels. Always the cells or the syncytium of 

 the ectoplacental cone conld be recognised. In some cases they 

 changed into young giant-cells, which in normal circumstances too 

 can originate from cells of the ectoplacental cone. Often spaces tilled 

 with maternal blood lay between the cells of the ectoplacental cone, 

 as is the case in normal egg-chambers. Rkichert's membrane could 

 easily be recognised as the homogeneous membrane that develops 

 beneath the trophoblastic epithelium when it changes into free 

 giant-cells. After the disappearance of the embryo the contraction 

 of the uterine wall had pressed the greater part of the ectoplacental 

 cone into the space previously occupied by the embryo. Moreover 

 this contraction had folded Reichkrt's membrane. Sometimes this 

 membrane had much diminished in size, but it always showed the 

 aperture through which the cells of the ectoplacental cone previously 

 cohered with the allantois. 



Generally the giant-cells very clearly showed their power to ingest 

 erythrocytes and other portions of the maternal decidual tissue, but 

 they had hardly changed in this group. This was not so in the 

 second group of empty egg-chambers where, as to the foetal elements, 

 only the distal entoderm of the yolk-sac, the membrane of Reichekt 

 and the giant-cells were left. There several of the latter cells had 

 grown out till they reached dimensions that were extraordinary 

 even for giant-cells. In normal egg-chambers it is the task of the 

 giant-cells to attack the decidual tissue and the maternal blood and 

 to leave part of the ingested food to the embryo. As soon as they 

 have been loosened from the trophoblastic epithelium or the ecto- 

 placental cone they lead an independent life. After the death of 

 the embryo the only change is the fact that of course the giant- 

 cells can provide no longer any food to the embryo. They keep 

 all to themselves and consequently thrive extraordinarily. In all 

 directions they acquire the same dimensions, as the pressure of the 

 embryo which in normal egg-chambers flattens them much, has 

 been suspended. Therefore the space occupied by the giant-cells is 

 much larger than in normal egg-chambers. Their number only seems 

 to me to be larger, because they are not dying away so soon as in 

 normal egg-chambers, not because more of them would have devel- 

 oped. Yet here too the fate of the giant-cells is to die away. This 

 is more conspicuous in another group of empty egg-chambers where 

 giant-cells are the only foetal element that is left. Especially here 

 one sees the body of the giant-cell losing its aftinity for the dyes 



