Inverse Inheritance
Mr. Galton contends that the reproductive elements become sterile when used in forming and maintaining the individual, and that only a small proportion of them are so used.68 He holds that the next generation will be formed entirely, or almost entirely, from the residue of undeveloped germs, which, not having been employed in the structure and work of the individual, have been free to multiply and form the reproductive elements whence future individuals are derived. Hence the singular inferiority not infrequently displayed by the children of men of extraordinary genius, especially where the ancestry has been only of a mediocre ability. The valuable germs have been used up in the individual, and rendered sterile in the structure of his person. Hence, too, the “strong tendency to deterioration in the transmission of every exceptionally gifted race.” Mr. Galton’s hypothesis “explains the fact of certain diseases skipping one or more generations,” and it “agrees singularly well with many classes of fact;” and it is strongly opposed to the theory of use-inheritance. The elements which are used die almost universally without germ progeny: the germs which are not used are the great source of posterity. Hence, when the germs or gemmules which achieve development are either better or worse than the residue, the qualities transmitted to offspring will be of an inverse character. If brain-work attracts, develops and sterilizes the best gemmules, the ultimate effect of education on the intellect of posterity may differ from its immediate effect.