In partial frigidity, the male must, apart from the preceding manipulations, have special regard to the expiration of the female excitation, even after congressus has begun. Cum muliebria humescent, fascinum inserendum est as far as possible and the motion following be exceedingly slight, hardly more than a tremor, while the root of the mentulæ compressa est contra clitoridem. Deinde actio propria incipiat. Cum climax propinquet fascinum extrahendum et, si necessitas, abstergendum est. Tum actio resumenda est. This procedure may be repeated again and again until the female approaches her orgasm so closely that she will not permit detractionem any more. The climax will then be simultaneous in both mates. The hygienic rule in regard to duration is hence briefly this: The man must adjust himself to the condition of the woman, so that both may reach the culmination at the same time. _Offspring._—The hygiene of the vita sexualis in relation to the offspring is of the greatest personal as well as social importance. The most favorable time for child-bearing is between the twenty-fourth and the fortieth year of the woman’s life. Before and after this time child-bearing is of disadvantage for the mother as well as for the child. The interval between two confinements should be no less than two and a half years. Twelve months for lactation, nine months for reparation from the nervous strain of lactation, and nine months for the next pregnancy. The maximum number of children compatible with health should thus not exceed seven. The moderate bearing of children, despite its physiological expense, is conducive to health. The middle part of the intermenstrual period is, as a rule, the most sterile. If the couple is anxious to have a child, the best time for concarnatio is from the third to the eighth day after the flow has ceased. The time from the fifth to the second day before menstruation is not so favorable as the days after the period. The greater part of conception follows concubitus practised in the eight days following menstruation.[CZ] Hence a couple desiring a child should be advised that the eight days following menstruation, while not absolutely dependable, yet present the most favorable time for conception. The time of the day most favorable for the congressio depends upon the purpose of the act, whether it is practised for the sake of procreation or for pleasure only. The horizontal position post initum favors the retention of the semen within the vagina, the erect position its expulsion. The motionless reclining position of the woman after the generative act is, hence, favorable to conception. The act, therefore, should not be practiced immediately before arising.[DA] The season is also claimed to have some influence upon the offspring.[DB]