An English edition of this celebrated American story seems called for by the great and increasing interest felt in the problem of property in the old and crowded countries of Europe. It is nearly a hundred years since Malthus expounded the true relation between poverty and the increase of the human race: and it is more than thirty years since Darwin, in his Origin of Species, showed that the Malthusian Law lies at the basis of all organic evolution. No further apology is needed for a tale which points to a discovery, already tested by experience, which claims to solve, at one and the same time, the Malthusian or population problem, the Darwinian or eugenic problem, the problem of social purity, and the problem of personal health in relation to sex.