Galton defined eugenics as the science of good breeding. Its aim as a pure science is to study the agencies under social control “that may improve or impair the racial qualities of future generations, either physically or mentally.” Galton’s program, as outlined by the founder shortly before his death, insisted upon (1) a study of the laws of heredity, (2) a dissemination of knowledge about heredity, (3) a study of the factors underlying marriage, (4) a study of birth rates, and (5) a case study of individual families. Eugenic social thought holds that heredity among human beings operates according to the same laws that govern heredity among animals. The theory of Mendelian units becomes in practice the theory of multiple factors. The unit characters, upon analysis, appear to be complex and to be inherited in complex ways. Multiple factors are inherited from generation to generation directly when pure factors are united with pure factors. But when the pure is united with the hybrid, then the laws of dominance and recessiveness operate. In such combinations certain factors tend to express themselves in greater proportion than do other elements. This failure to secure expression in a given generation, however, means that the specific factor is recessive for the time being. Later, it will likely appear. Galton stated another important eugenic law, the law of regression. Each peculiarity is inherited by the offspring on the average in a slightly less degree than it is found in the parent. Hence, according to Galton, good traits and poor traits alike are inherited in a degree nearer mediocrity by the offspring than by the parents. This law partially explains why gifted men rarely have sons who are equally gifted. The law seems to hold good for large numbers, but not when considered in relation to single families. It serves as a check upon variation and mutation. Galton and Pearson advanced another statistical law, the law of ancestral inheritance. Galton supposed that the parents contribute to the child one-half of his inherited factors, the grandparents one-fourth, and so on. Pearson has secured statistical evidence which shows that Galton’s geometric series is incorrect, and that on the average in a large number of cases the parents together contribute to the child .624 of his traits; the four grandparents, .198; the eight great grandparents, .063; and so on. The law of mutation, described by de Vries and other geneticists, refers to the appearance of mutants, or individuals who do not reproduce to form but represent a new line of heredity. In this way the appearance of genius may often be accounted for. However, the factors which explain the appearance of mutants have not yet been analyzed.