Its eugenics is to be effected through the mental exertion of mothers. And we have lately been in correspondence with a western attorney who is endeavoring to form an association of persons who will agree to be the parents of "willed" children. By this means, he has calculated (and sends a chart to prove it) that it will require only four generations to produce the Superman.

Life and Letters of Charles Darwin, Vol. I, p. 302, New York, 1897. The letter is dated 1844.

Goddard, H. H., Feeble-mindedness, p. 359. New York, the Macmillan Company, 1914.

For a review of the evidence consult an article on "Telegony" by Dr. Etienne Rabaud in the Journal of Heredity, Vol. V, No. 9, pp. 389-400; September, 1914.

It will be recalled that the coefficient of correlation measures the resemblance between two variables on a scale between 0 and-1 or +1. If the correlation is zero, there is no constant relation; if it is unity, any change in one must result in a determinate change in the other; if it is 0.5, it means that when one of the variables deviates from the mean of its class by a given amount, the other variable will deviate from the mean of its class by 50% of that amount (each deviation being measured in terms of the variability of its own class, in order that they may be properly comparable.)