I have shown that asceticism is an immoral principle, the action of which tends to fill individual life with gloom and depression, and to thwart or counteract general happiness. I have also shown the absolute necessity for retarding the multiplication of human beings to suit the limits of available subsistence. And now, after pointing out that philoprogenitiveness—which is the groundwork of domestic and social virtue, and ought to be the mainspring of reproduction of species—is continually liable to be strained, depressed or perverted into anti-social bitterness in parental bosoms among the lower classes, I must ask the question: How otherwise than by the easiest method known to science could the difficulties of the position be met and overcome? Messrs. Patrick Geddes and J. A. Thomson, in their treatise on the _Evolution of Sex_, urge the necessity of what they call “an ethical rather than a mechanical prudence after marriage, of a temperance recognized to be as binding on husband and wife as chastity on the unmarried.” (_The Evolution of Sex_, p. 297.) But what do these gentlemen mean by the temperance here recommended? It is surely well known that the birth of a large family is perfectly consistent with a sparing, most temperate exercise of the procreative function; and surely also it would be folly on our part to look for parental conduct controlled by ethical motive in the warrens of the poor of our large cities, from whence springs an important section of the national life. (_Social Control of the Birth Rate_, Pamphlet by G. A. Gaskell.) In the homes of the upper classes, adorned with all the amenities and refinements of civilization, parental prudence results mainly from egoistic motive. Practical reformers will hesitate to assume that those—the less favoured social units—are likely to surpass these in moral elevation, and demean themselves generally in a superior manner! But further, a parental prudence, dispensing with mechanical methods of checking propagation, may even prove the converse of ethical conduct. Advanced sexual morality requires a free and healthful exercise of sexual function. That such freedom is not possible under present social conditions is irrelevant to the question at issue; the point is that conduct unnecessarily traversing this advanced sexual morality is not in accordance with rationalized social ethics; it has no scientific basis. Parental morals must conform to the principle indicated by Herbert Spencer—reduce to a minimum the sacrifice of individual life and happiness to the life of the species; augment to the maximum the joys of affection involved in parental relations. This is possible to a race among which are beings of low intelligence and unrestrained passion only by bringing into play the laws of heredity through rational breeding. But rational breeding depends on an appeal to ordinary egoistic motive and practical resort to the painless mechanical means of checking conception.