The practice of obstetrics, designed for the use of students and practitioners of medicine . s (allantoic stalk); vl, anteriorbody-wall in the region of the heart. In figures 2 and 3 the amniotic cavity has, for the sake of clearness, been drawn toolarge. The cavity of the heart has everywhere been represented too small and manydetails, more particularly the body of the embryo, have, with the exception of figure 5,simply been shown schematically. 64 PHYSIOLOGICAL PREGNANCY. of a plate which gives rise to the three layers, the ectoderm becoming continuouswith Raubers layer. The entoderm grows a
The practice of obstetrics, designed for the use of students and practitioners of medicine . s (allantoic stalk); vl, anteriorbody-wall in the region of the heart. In figures 2 and 3 the amniotic cavity has, for the sake of clearness, been drawn toolarge. The cavity of the heart has everywhere been represented too small and manydetails, more particularly the body of the embryo, have, with the exception of figure 5,simply been shown schematically. 64 PHYSIOLOGICAL PREGNANCY. of a plate which gives rise to the three layers, the ectoderm becoming continuouswith Raubers layer. The entoderm grows around inside the ectodermal layerand forms the hollow yolk-sac The splanchnopleure never completely investsthe yolk, as it does in the chick; the somatopleure forms the amnion outsidethe embryo and a chorion which separates from the amnion (Fig. 69); theprincipal modification consisting in the fact that as the mesoderm does notextend to the ventral limit, the chorion, composed of ectoderm and mesoderm, CAorion /70/if/osf/m Jfeadof£7nAryo f/z/iht/rmlVesLclc (Af/vp/iruvijrJ Amnionicfarify. J/i/esiinal^^^^^^ Caruil. C/u>rioni^eye Fig. 94.—Schematic Representation of Early Embryonic Structures. is not completed on the ventral side. This interval is completed by the simplelayer of ectoderm forming Raubers layer. The modification is still furtheremphasized by the atrophy and disappearance of the cells of this layer. Thefacts just stated have given rise to many ill-founded theories with regard tohuman development; thus, Raubers layer was supposed to have no relationto the true ectoderm, and as the entoderm seemed to come to the surface, it wassupposed that there was a so-called inversion of the germ-layers.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectobstetrics, bookyear1
