Mrs. Duffey, in mentioning this theory, very shrewdly adds: “He does not, however, tell us what would be the result if the germ and the sperm should proceed, the one from the right ovary and the other from the left testicle.” The fact also remains that a man who has been deprived of one testicle has become the father of children of both sexes. Also, that a woman having lost one ovary has conceived and brought forth both sons and daughters. Prof. Thury, of Geneva, gives the following theory: That if impregnation takes place immediately or very soon after menstruation, the child will be a female; but if not till some days later, the child will be a male. This theory is pretty generally depended upon by stock breeders, who claim that _early_ union after _heat_ produces _females_, while the _late_ produces _males_. Yet Darwin affirms that the results of experiments have gone far to disprove Thury’s theory. Girou, a French scientist, as well as some French and German physiologists, claims that experiments show that if the male is older and stronger than the female, the offspring will be more largely males, and _vice versa_. _Samuel Hough Terry_ gives as a tested and proved theory that if the wife is in a higher state of sexual vigor and excitement at the time of conception, boys will be conceived; but if the reverse is true, girls will be the result. A study of these various theories confirms our doubts as to whether the true law has as yet been discovered. If, as I believe, sex is in the soul, then the sex of offspring must be determined by a law of the soul. So far human knowledge has not arrived in its investigations at sufficient data for understanding that law. The probabilities are that it will eventually be proven that the parent whose mental forces previous to, and at the time of conception, are most active and vigorous, controls the sex of the child. Facts proving any of the above theories are solicited. The _desirability and practicability of limiting offspring_ are the subject of frequent inquiry. Fewer and better children are desired by right minded parents. Many men and women, wise in other things of the world, permit generation as a chance result of copulation, without thought of physical or mental conditions to be transmitted to the child. Coition, the one important act of all others, carrying with it the most vital results, is usually committed for selfish gratification. Many a drunkard owes his life-long appetite for alcohol to the fact that the inception of his life could be traced to a night of dissipation on the part of his father. Physical degeneracy and mental derangements are too often caused by the parents producing offspring while laboring under great mental strain or bodily fatigue. Drunkenness and licentiousness are frequently the heritage of posterity.