According to _Ferdy_ and other authors, the neck of the womb, during the venereal orgasm of the woman, executes movements of suction in the glans penis. I do not know if this is a fact, but it is certain that the female orgasm is useless for conception. Absolutely cold women, incapable of the least voluptuous sensation are as fruitful as those who have pronounced venereal orgasms. It proves that the spermatozoa arrive at their goal even when the womb is entirely passive. The great variation of sexual desire in different individuals renders mutual adaptation often very difficult. The venereal orgasm is sometimes more rapid in man, sometimes in woman (more rarely in the latter). This inequality is rather to the detriment of the woman, for the man can still satisfy himself when the orgasm of the woman has terminated, while the contrary is not possible without artificial manipulation. Moreover, the frequence and intensity of the sexual appetite are often much greater in one than in the other, which is detrimental to both. Here again it is the woman who suffers the most, for the man can always satisfy himself without the woman having voluptuous sensations. What is commonly called good manners generally prevents the conjoints from speaking of their sexual desires before marriage. This very often results in grave deceptions, dissensions, and often even divorce. I shall return to this subject in Chapter XIV. Voluptuous sensations only represent the means employed by nature to bring together the sexes with the object of reproducing the species. A woman can be fecundated and give birth to a child by the aid of semen injected into the uterus by a syringe. Moreover, it is rather exceptional for the venereal orgasm to occur in the two sexes at the same moment. It is essential for fecundation that the semen should enter the womb. When the spermatozoa have reached the neighborhood of the neck of the womb they swim by their own movements, not only along the whole uterine cavity, but also along the Fallopian tubes and even in the abdominal cavity, so that the force of ejaculation is of little importance. =Pregnancy.=--The womb enlarges considerably during pregnancy. It exceeds the size of an adult head, and the muscles of its walls are greatly increased, so as to be capable of expelling the child later on.