Eugenic social thought is the child of biological discoveries. Eugenics, the science of good breeding, which did not achieve scientific standing until the closing years of the last century, may be traced back in its incipient forms to Plato, who advocated that strength should mate only with strength, and that imperfect children should be eliminated from society. In its scientific origins eugenics dates from 1859, when Darwin’s _Origin of Species_ was first published. Its beginning as a distinct field of human thinking is found in the articles by Francis Galton on “Hereditary Talent and Genius,” which appeared in 1865; and in 1869, in book form under the title, _Hereditary Genius_.[XIX-1] Eugenic social thought deals with the operation of the laws of heredity in society. It was a part of this field which Francis Galton made world-known by his treatises on _Hereditary Genius_ and _Inquiries into the Human Faculty_.[XIX-2] In 1904, Galton wrote a paper entitled: “Eugenics; Its Definition, Scope and Aims.” In this dissertation the new science of eugenics was formally introduced to the world. Gabon’s analysis of eugenics became its leading interpretation.[XIX-3] The mantle of the founder fell upon Professor Karl Pearson, whose work at times has assumed a distinctly statistical nature. Professor Pearson’s leaning toward biometry has brought severe criticism upon him. The statistical approach, while exact and thought-provoking, is subject to various errors in interpretation of data. The viewpoint from which Professor Pearson writes, however, is not one-sided. For example, he states that “it may require years to replace a great leader of man, but a stable and efficient society can only be the outcome of centuries of development.”[XIX-4] He holds that group conscience ought for the sake of social welfare to be stronger than private interest, and that the ideal citizen should be able to form a judgment free from personal bias.[XIX-5] C. W. Saleeby, another English writer, has developed an independent reputation as a eugenist.[XIX-6] In the United States, such men as C. B. Davenport[XIX-7] and Paul Popenoe have made important eugenic contributions. The recent tendency has been to be wary of purely statistical studies of heredity and to rely more definitely upon case studies. However, since eugenics is directly indebted to the studies of heredity and since heredity must be investigated for several generations, eugenic social thought has not yet developed far.