Here it becomes developed into a full grown foetus, and is brought forth about forty-two weeks from the time of conception by a process termed parturition. But one grand question is, how the semen operates itself, or any part thereof reaches the ovary, and if so, in what way it is conveyed to them. It was long the opinion that the semen was ejected into the uterus in the act of coition, and that it afterward, by some unknown means, found its way into and along the Fallopian tubes to the ovary. But there are several facts which weigh heavily against this opinion, and some that entirely forbid it. In the first place, there are several well attested instances in which impregnation took place while the hymen remained entire, where the vagina terminated in the rectum, where it was so contracted by a cicatrix as not to admit the penis. In all these cases the semen could not have been lodged anywhere near the mouth of the uterus, much less ejected into it. Secondly, it has followed a connection where from some defect in the male organs, as the urethra terminating some inches behind the end of the penis, and it is clear that the semen could not have been injected into the uterus, nor even near its mouth. Third, the neck of the unimpregnated uterus is so narrow as merely to admit a probe, and is filled with a thick tenacious fluid, which seemingly could not be forced away by any force which the male organ possesses of ejecting the semen, even if the mouth of the male urethra were in opposition with that of the uterus. But fourth, the mouth of the uterus is by no means fixed. By various causes it is made to assume various situations, and probably the mouth of the urethra rarely comes in contact with it. Fifth. "The tenacity of the male semen is such as renders its passage through the small aperture in the neck of the uterus impossible, even by a power of force much superior to that which we may rationally suppose to reside in the male organs of generation." Sixth. "Harvey and DeGraaf dissected animals at almost every period after coition for the express purpose of discovering the semen, but were never able to detect the smallest vestige of it in the uterus in any one instance."* * Dewees' Essay on Superfoetation.--Author's note. Aware of the insurmountable objection to this view of the manner in which the semen reaches the ovary, it has been supposed by some physiologists that the semen is absorbed from the vagina into the great circulating system, where it is mixed, of course, with the blood, and goes the whole round of the circulation subject to the influence of those causes which produce great changes in the latter fluid.