The origin of tumours on the principle now adopted depends essentially on that reverse of the principle of individuation, illustrated in plural births. One most striking expression of nutritive degeneracy is hæmophilia or the diathesis of the "bleeders." This, as Potain has pointed out, is not met with except in families which are subject to nutritive or graver degeneracies. Dent has shown that definite mental peculiarities, especially an inability (stronger than unwillingness) to tell the truth, are especially common in bleeders.[241] Hæmophilia was frequently encountered in the Valois[242] family, and has been met with in the descendants of Ernest the Pious of Hanover. The condition, as Osler,[243] of Baltimore, points out, is characterised by a tendency to uncontrollable bleeding, either spontaneous or from slight wounds. The hereditary transmission in this disorder is decided. In the Appleton-Swain family, of Reading, Mass., there have been cases for nearly two centuries. Instances have already occurred in the seventh generation. The usual mode of transmission is through the mother, who is not herself a bleeder, but the daughter of one. Atavism through the female is the rule. The daughters of a bleeder, though healthy and free from any tendency, are almost certain to transmit the disposition to the male offspring. The affection is much more common in males than in females, the proportion being estimated at 11 to 1, or even 13 to 1. The tendency usually appears within the first two years of life. It is rare for manifestations to be delayed until the tenth or twelfth year. Families in all conditions of life are affected. Bleeders, like other degenerates, may have large families; the members usually have fine soft skin. In all probability, as the researches of Cohn show, this condition is due to incomplete inhibition, resultant in excessive activity of the blood-making organs. Such inhibition is, of course, cerebral, and hence, as a later acquirement, readily affected by degeneracy which may find its chief expression in this defect.