39. The time at which the Ovulum enters the womb after fecundation is not precisely known. (Meckel.) The fimbriated end of the fallopian tube has been found actually applied to a Graafian vesicle after copulation. (Magendie.) An ovulum, containing the rudiments of an embryo has been observed in the human subject half engaged within the tube, and half still resting on the Ovarium. (Bussieres.) The Ovulum has been detected on its way through the fallopian tube.—(Burns, Haighton, Cruikshank, Prevost, Dumas.) It is said to have been detected in the uterine cavity on the eighth day. (Home.) Although it has lately been the fashion to doubt the accuracy of such a fact, there is reason to believe it to be correct, from the circumstance of M. Bauer’s microscopian examination of that Ovulum and description of its structure corresponding with more recent discoveries. (Boer.) The embryo contained in an Ovulum of a week’s growth has been seen and measured. (Autenrieth _Supplementa ad Historiam Embryonis Humani_.) The Ovulum, until the eighth day, has been observed in the uterus under a gelatinous form by another anatomist. (Walker.) Ovula in the fallopian tubes have also been seen on the eighth day by Prevost and Dumas. 40. I have had occasion, within the last two months, to see a perfect Ovulum ejected from the womb fourteen days after a single sexual congress, which had taken place the day after the cessation of the menses. Dr. Pockels (Isis, December 1825,) examined more than fifty human Ova, among whom four had been expelled from the womb between the eighth and sixteenth day after conception. On the fourteenth day the Ovulum is about the size of a Spanish nut. The chorion is surrounded by a thick membrane[7]. 41. An Ovulum at three weeks is mentioned by Hunter (Gravid Uterus). At twenty-two days a perfect Ovulum, with the embryo clearly defined, was shewn by Dr. Combe to Dr. Baillie. Blumenbach asserts seeing an Ovulum of the size of a small cherry, which could not have had more than twenty-three days’ existence. M. Ogle’s case, published in the “Transactions of the Society for the Improvement of Medical and Surgical Knowledge”, was one of an Ovulum in Utero at five weeks. These facts contradict Burns’ assertion, that at “three weeks or a month after impregnation no fœtus is in the uterus.” 42. After being safely lodged within the cavity of the womb, the Ovulum continues to grow on its own life-principle, for a while, until its connection with the mother is effected, through the medium of the deciduous membrane, which becomes, at a more advanced period, as it were, a new and additional covering to the Ovulum. The growth of the Ovulum causes the _cortex_ to burst, as happens with the receptacle or cortex of certain seeds, and with the outer shell of the ova of some oviparous animals. (See Plate I., fig. 1, 2, 3, 4.)