15. A WANT OF DESIRE may often prevail, and may be caused by loss of sleep, study, constant thought, mental disturbance, anxiety, self-abuse, excessive use of tobacco or alcoholic drink, etc. Overwork may cause debility; a man may not have an erection for months, yet it may not be a sign of debility, sexual lethargy or impotence. Get the mind and the physical constitution in proper condition, and most all these difficulties will disappear. Good athletic exercise by walking, riding, or playing croquet, or any other amusement, will greatly improve the condition. A good rest, however, will be necessary to fully restore the mind and the body, then the natural condition of the sexual organs will be resumed. 16. HAVING TWINS.--Having twins is undoubtedly hereditary and descends from generation to generation, and persons who have twins are generally those who have great sexual vigor. It is generally the result of a second cohabitation immediately following the first, but some parents have twins who cohabit but once during several days. 17. PROPER INTERCOURSE.--The right relation of a newly-married couple will rather increase than diminish love. To thus offer up the maiden on the altar of love and affection only swells her flood of joy and bliss; whereas, on the other hand, sensuality humbles, debases, pollutes, and never elevates. Young husbands should wait for an _invitation to the banquet_, and they will be amply paid by the very pleasure sought. Invitation or permission delights, and possession by force degrades. The right-minded bridegroom will postpone the exercise of his nuptial rights for a few days, and allow his young wife to become rested from the preparation and fatigue of the wedding, and become accustomed to the changes in her new relations of life. 18. RIGHTLY BEGINNING SEXUAL LIFE.--Intercourse promotes all the functions of the body and mind, but rampant lust and sexual abuses soon destroy the natural pleasures of intercourse, and unhappiness will be the result. Remember that _intercourse_ should not become the polluted purpose of marriage. To be sure, rational enjoyment benefits and stimulates love, but the pleasure of each other's society, standing together on all questions of mutual benefit, working hand in hand and shoulder to shoulder in the battle of life, raising a family of beautiful children, sharing each other's joys and sorrows, are the things that bring to every couple the best, purest, and noblest enjoyment that God has bestowed upon man. {206} [Illustration: A TURKISH HAREM.] Sexual Proprieties and Improprieties. 1. To have offspring is not to be regarded as a luxury, but as a great primary necessity of health and happiness, of which every fully-developed man and woman should have a fair share, while it cannot be denied that the ignorance of the necessity of sexual intercourse to the health and virtue of both man and woman is the most fundamental error in medical and moral philosophy.