The law of heredity winds like a red thread through the family history of every criminal, of every epileptic, eccentric and insane person. And we should sit still and watch our civilization go into decay and fall to pieces without raising the cry of warning and applying the remedy? The sexual appetite is very pronounced in tuberculous persons. They marry and beget children in the most wanton fashion. The law cannot and does not prevent them, and the carnal instinct is not to be killed. What is to be done when law and religion forbid the application of preventive measures and even prosecute the person that recommends them? Local diseases and pathological conditions in the woman (at times in man also) within wedlock, may render parturition and immediate danger to the life of the mother or of the child, or of both together. Surely in such cases it is the bounden duty of the physician to intervene and counsel against, nay absolutely forbid impregnation. Well, how is it to be done? Must husband and wife who love each other be separated? It would be unnatural, in fact it is quite impossible. Or should they abandon sexual intercourse altogether and live like brother and sister? Well, a few exceptionally cold natures may have will power enough to carry into effect such a pact. But in 99 out of 100 cases the interdict of the sexual act sends the husband to satisfy his cravings elsewhere and contract disease, or he falls in love with another woman and wrecks home and family. Similar conditions may be brought about by other causes as well. Take for instance, the poor working man, or mechanic, who has already six or seven children, and whose wife is unusually fertile, giving birth to children year after year. The wages of the father do not suffice to properly support them all. The food that can be purchased with the slender means is not at all adequate. Rent and other bills fall behind and they get in debt. They are both young yet. What is to be done? If they follow the natural law there will be an increase in the family every year. Moreover, these ever-recurring labors weaken the constitution of the mother and sap away her strength. Starvation? Sexual continence in wedlock? It is curious indeed to hear rich men, well fed clergymen, pious zealots and reformers, leaning back in comfortable chairs discussing this burning question and bewailing the immorality of the common people. Statistics prove that these very people who extol to the poor all the blessings of a poor family never live up to their teachings, either in theory or in practice. The majority of these apostles of morality have no children at all or at the utmost two or three. Why should that be so? What interesting reading it would make if the sexual history of these persons were followed up and printed.