Such is the teaching of eugenics. It is not wholly new. The early Greeks gave much thought to it, and with the insight which characterized them, they rightly put the emphasis on the constructive side; they sought to breed better men and women, not merely to accomplish a work of hygiene, to lessen taxes, and reduce suffering, by reducing the number of unfortunates among them. As early as the first half of the sixth century B. C. the Greek poet Theognis of Megara wrote: "We look for rams and asses and stallions of good stock, and one believes that good will come from good; yet a good man minds not to wed an evil daughter of an evil sire, if he but give her much wealth.... Wealth confounds our stock. Marvel not that the stock of our folk is tarnished, for the good is mingling with the base." A century later eugenics was discussed in some detail by Plato, who suggested that the state intervene to mate the best with the best, and the worst with the worst; the former should be encouraged to have large families, and their children should be reared by the government, while the children of the unfit were to be, as he says, "put away in some mysterious, unknown places, as they should be." Aristotle developed the idea on political lines, being more interested in the economic than the biological aspects of marriage; but he held firmly to the doctrine that the state should feel free to intervene in the interests of reproductive selection. For nearly two thousand years after this, conscious eugenic ideals were largely ignored. Constant war reversed natural selection, as it is doing to-day, by killing off the physically fit and leaving the relatively unfit to reproduce the race; while monasticism and the enforced celibacy of the priesthood performed a similar office for many of the mentally superior, attracting them to a career in which they could leave no posterity. At the beginning of the last century a germ of modern eugenics is visible in Malthus' famous essay on population, in which he directed attention to the importance of the birth-rate for human welfare, since this essay led Darwin and Wallace to enunciate the theory of natural selection, and to point out clearly the effects of artificial selection. It is really on Darwin's work that the modern science of eugenics is based, and it owes its beginning to Darwin's cousin, Francis Galton. Galton was born in 1822, studied mathematics and medicine, traveled widely, attained fame as an explorer in South Africa, and after inheriting sufficient income to make him independent, settled down in London and gave his time to pioneering experiments in many branches of science. He contributed largely to founding the science of meteorology, opened new paths in experimental psychology, introduced the system of finger prints to anthropology, and took up the study of heredity, publishing in 1865 a series of articles under the title of "Hereditary Talent and Genius," which contained his first utterances on eugenics.