The due occurrence of the phenomena just detailed does not necessarily secure, although it generally succeeds in producing, a prolific result. Health, aptitude, and one important condition, are indispensable; and the last is—a positive contact between the male sperm and female ovum. There are many remarkable eccentricities that embitter married life. A union may exist between two parties who are wholly inapt for mutual enjoyment. The sensations belonging to the sexual act are involuntary, and are provoked independently of the will: hence, in connexion without consent, or under feelings of great repugnance, the orgasm is sometimes aroused; and yet, where the greatest affection and desire prevail, the male oftentimes unseasonably concluding before the female, is a most tantalizing source of disappointment. Further allusions will be found to this subject under the heads of “Sterility,” and “Impuissance.” As a preliminary aid to the description of the process of impregnation, which ensues, the following anatomical draft is presented:— [Illustration: 1. Section of the womb, upper part. 2. Do. of side. 3. Do. of lateral covering. 4. Do. of lower part of womb. 5. Cavity of the womb. 6. A prominence leading from the openings of the fallopian tubes. 7. The vagina. 8 and 9. Fallopian tube cut open. 10 and 16. The fimbriated extremity of do. 11. The pavilion. 12. The ovary. 13. Vesicles in do. 14. Continuation of ovary. 15. Ligament of do. 17. Pavilion of right ovary. 18. Right ovary. 19. Connecting band.] Man, unlike other animals, is not smitten with desire to propagate only at particular periods. In sentient beings, every season is favorable to the flame of love. When conception takes place, the following phenomena are believed to occur: The womb is supposed to participate in the excitement of the sexual act, and at the moment of the orgasm, to receive the male seed, and to mingle with it a fluid of its own. The whole apparatus of the uterus appears influenced at the same time,[8] by a kind of electric irritability. A vesicle, owing to the ovaria being grasped or embraced by the fimbriæ, escapes from its lodgment and enters the fallopian tube, where it bursts, and its albuminous drop is conveyed into the womb. From the circumstance of the male semen returning from the vagina after copulation, it has been doubted whether it was intended to enter the uterus. It certainly can only enter once,[9] and that when impregnation takes place; and even then a small portion suffices, for immediately after conception the mouth of the womb becomes impermeably closed. The mouth of the womb lies horizontally, like the lips of the face, while that of the orifice of the urethra is arranged perpendicularly: hence the presumption, from this better adaptation to transmit and receive, that the semen to impregnate should enter the uterus.