Talk:Paper - On a normal human ovum not over 7.5 days of age

On a normal ovum of approximately 9 to 10 days of age. Arthur T. HERTIG and John ROCK, Free Hospital for Women, Brookline, Mass., Departments of Pathology, Obstetrics and Gynecology, Harvard Medical School, and Department of Embryology, Carnegie Institution of Washington. The ovum (Carnegie 8215) was discovered in a uterus removed surgically on the fifty-sixth day of .the menstrual cycle (periodicity infrequent and irregular). Endometrial histology indi- cated a typical twenty-fourth day secretory phase with ovulation having occurred approximately 10 days before. The implantation site was posterior, at the corm opposite the ovary of origin, and without visible vascular response. It appeared as a slight elevated area measuring 0.57 mm. in diameter surmounted by a tiny 0.115 X 0.154 mm. area of ulceration. The chorion measures 0.207 X 0.498 X 0.525 mm.; the chorionic cavity 0.100 X 0.210 X 0.228 mm.; the embryo 0.050 X 0.052 X 0.084 mm. and the amniotic cavity 0.022 X 0.048 X 0.050 mm. The ovum is nearly completely embedded within a rather markedly vascular but relatively ischemic endometrium showing only minimal predecidual response. The trophoblast, indifferent at the abembryonic pole, possesses elsewhere an inner cytotrophoblast and an outer, lacuna- riddled, blood-filled syncytiotrophoblast. The nearly globular, normally situated, bilaminar germ disk shows early vacuolization of its ectoderm. The amnion is well formed but still lightly attached to its parental trophoblast. Mesoblast formation is active with development of the exocoelomic (Heuser’s) membrane. Angiogenesis is absent within the chorionic cavity. Focal accumulations of cytotrophoblast - primordia of chorionic villi - are beginning to appear.