Mertens. Beiträge zur normalen und pathalogischen Anatomie der menschlichen Placenta. (Zeitsch. F. Geb. und Gyn., XXX Bd., Hft. 1 and XXXI Bd., Hft. 1). About normal and pathological anatomy of the human placenta

After detailed literary studies on comparative anatomy and based on the preparation of a very young human egg, the author resolves the controversial issue of the nature and origin of the cover of chiral villi in the following way. In humans, as in other animals, the cover of chorial villi of the dancer consists of two layers, one cellular layer originating from the embryo (ectoderm) and the other protoplasmic, which is a modified uterine epithelium (syncytium). Already at the beginning of the insertion of the egg, both of these layers are so tightly interconnected that they form, as it were, one tissue layer, on which it is not difficult, however, to distinguish its initial constituent elements.