34. As soon as the Ovulum has departed from its vesicular nest in the Ovarium, the cavity which remains begins to fill up with a yellow substance, different in texture from the surrounding tissue of the Ovarium, and having, generally, a radiated centre of a whiter colour. This is the corpus luteum. (Plate IX., page [30] and [31]; also, Spec. 3468 B and C, Gallery College of Surgeons, and Dr. Agar’s case Royal College of Physicians[[4]].)
35. The presence of corpora lutea in the Ovarium of women, is always an indication that as many ovula have escaped from that organ; but it is not necessarily an evidence that the individual has been impregnated, as ovula have escaped without the congress of the two sexes.
36. It is inaccurate, therefore, to state that a woman has been pregnant because a corpus luteum has been found in one of the Ovaria after death, or to calculate the number of children she has borne from the number of corpora lutea so detected. Corpora lutea have been found in the Ovaria of very young girls, of unmarried women of the strictest virtue, in newly-born female infants, and lastly, in sterile animals, such as mules. (Brugnone, Joer. Roose.)
37. Sir Everard Home’s notion that the corpus luteum was formed first, and that, too, independently of sexual congress, and that the Ovulum was formed afterwards, is disproved by more accurate and recent observers. (Boer, Plagge.) There is reason to believe that Sir E. Home had been too precipitate in his inquiry[[5]].
38. The Ovulum, on entering the womb, is about the size of a small pea. The cavity, on the contrary, into which it enters, from the very first, is of considerable dimensions. One cannot help being struck at this great disparity in the relative dimensions of the Ovulum and the cavity of the womb. When they first come in apposition, that of the latter is from ten to twenty times greater than that of the former. (See Sir W. Blizard’s case, Royal College of Surgeons, and Spec. 73, 75, 76, in Sir C. Clarke’s Collection[[6]].)
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.)
43. On the cortex bursting, the lanuginous or fibrillous membrane within it (21) is exposed, when the fibrils will forthwith entwine themselves with the flocculi of the decidua, and thus the Ovulum fastens itself to the uterus by one or more contiguous points. (Carus.)