Dispareunia of the two mates is often of great importance for the offspring. Orgasmus retardatus in the male does not cause dispareunia. In such a case concarnatio may be protracted for hours without interference by the muliebria. But when the male tends to reach the orgasm too quickly for his particular mate and the erection ceases, then the female orgasm does not take place at all, and we have a case of dispareunia. Now, at the moment of the female orgasm the uterine suction takes place, by which sperma is drawn into the uterine cavity. Hence if the male orgasm occurs too soon and the woman does not reach this stage at all, female ejaculation and uterine suction fail to appear. This circumstance may seriously interfere with the entrance of the spermatozoa into the uterus and thus prevent conception.[DC] The male, therefore, has to be taught to prevent his premature orgasm by an effort of the will or by so varying the motions as to delay the climax. He has to retard his orgasm so that both mates may reach the culmination at the same time. Sometimes the entrance of the spermatozoa is prevented by a diseased or narrow cervical canal. In this case the repeated application of the constant electric current, after Apostoli, with the kathode in the uterus, will cause a cure of the catarrh and a more lasting dilation of the cervix than all the instrumental dilatations and the usual curettages will ever effect. While in the interest of the offspring the horizontal position of the woman after initus is most desirable, and concarnatio should hence take place in the beginning of the night, the rules are somewhat different, if initus is practised for libido only. Initus is slow and dangerous immediately after a meal and during the two and three hours which the first digestion needs, or after having finished a rapid walk or any other violent exercise. In the same way, if the mental faculties are excited by some mental effort, by a theatre party or a dance, rest is necessary, and it is advisable to defer amatory delights till the next morning. After the calm and the rest of the night the bodily organism and the intellectual faculties are in a happy serenity and the sensibility has the whole virginity of its impressions. On the other hand, initus ought to be avoided in the morning immediately before rising. The time for beginning daily occupations is by no means favorable to the attainment of a happy lassitude. The most propitious hour for initus is, therefore, during the night after the first sleep.