As regards sexual power we must distinguish between that of copulation and that of fecundation. The power may exist without the latter, when the testicles have ceased to functionate, while the other glands, in particular the prostate, second the venereal orgasm by their secretion, when the power of erection is still preserved. Inversely, the testicles may contain healthy spermatozoa in the impotent. In this case artificial fecundation by the syringe is practicable. =Individual Variations in Sexual Power.=--The fact that there are men who for several years can copulate several times a day proves to what extent sexual power varies in man. Sexual excitation and desire may sometimes attain such a degree that they are repeated a few minutes after ejaculation. It is not rare for a man to perform coitus ten or fifteen times in a single night, in brothels and elsewhere, although such excess borders on the domain of pathology. I know a case in which coitus was performed thirty times. I was once consulted by an old woman of 65 who complained of the insatiable sexual appetite of her husband, aged 73! He awakened her every morning at three o'clock to have connection, before going to work. Not content with this, he repeated the performance every evening and often also after the mid-day meal. Inversely, I have seen healthy looking husbands, at the age of greatest sexual power, accuse themselves of excess for having cohabited with their wives once a month or less. The reformer, _Luther_, who was a practical man, laid down the average rule of two or three connections a week in marriage, at the time of highest sexual power. I may say that my numerous observations as a physician have generally confirmed this rule, which seems to me to conform very well to the normal state to which man has become gradually adapted during thousands of years. Husbands who would consider this average as an imprescriptible right would, however, make wrong pretensions, for it is quite possible for a normal man to contain himself much longer, and it is his duty to do so, not only when his wife is ill, but also during menstruation and pregnancy. The question of sexual relations during pregnancy is more difficult, on account of its long duration. In this case caution is necessary, but total abstinence from sexual connection is, in my opinion, superfluous.