32. Into this chamber, then, so lined and so prepared the fecundated ovulum, in the condition described by Professor Boer, is received after its journey from the ovarium through the fallopian tube. 33. The pre-existence of an ovulum in the Vesiculæ Graafianæ, or Ovarian Vesicles—and its metamorphosis, after fecundation (14, 15, 16, 17, 18,) have been amply confirmed by Plagge of Bentheim, who published an account of his experiments and observations, illustrated by figures, in Meckel’s Journal of Physiology. (See also Prevost and Dumas, 3rd memoir.) 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].)