The Marital Relation.-- It is most important for the interest of both parties that there should be chastity in the marriage relation as well as out of it. Many young couples have had their lives ruined by excessive sexual indulgence. The effect is usually most severe upon the husband, yet the wife becomes weak, nervous, and excitable. Sexual excess is also the grave of domestic affection. The general rule given is that coitus should never take place oftener than every seven or ten days. When coitus is succeeded by langour, depression, or malaise, it has been indulged in too frequently. Among civilized people there are three widely diferent views as to the proper course to be pursued: First, those who maintain that sexual intercourse should not take place except for the propagation of the species. Second, those who believe that the act is a love relation, mutually demanded and enjoyed by both sexes, and serving other purposes besides that of procreation. Third, those who hold that sexual intercourse is a physical necessity for the man, but not for the woman. The first theory, "that the sexual relations should never be sustained save for the purpose of procreation," has many advocates. They teach that there are other uses for the procreative element than the generation of offspring, and far better uses than its waste in pleasures. They claim that a life of total chastity increases the physical and mental vigor; and there will result a procreation on the mental and spiritual planes, instead of on the physical ones. They also claim that to woman belongs the creative power; that she must choose when a new life shall be evolved; and that only by adhering to this law can she be protected in the highest function of her being-- the function of maternity. The adherents of the second theory, "that the act is a love relation, mutually demanded and enjoyed by both sexes, and that it serves other purposes besides that of procreation," claim that the female sexual life indicates that the healthy woman is neither indifferent nor passive in the generative act. It has much the same effect as in man-- a powerful increase in her sensations, whole groups of muscles are set in motion, and the uterus as well as the entire nervous system are in an excited condition and activity. And that it is the province of the mother to decide when a new life should begin. The third theory, "that sexual intercourse is a physical necessity for the man, but not for the woman," is by far the most widely accepted. We will consider, first, the practical results of this last theory; and, second, the scientific basis on which it rests. It is generally acknowledged that this practice has done more to cause domestic misery, sickness, and death than that dreadful scourge of the human race, tuberculosis.