_Fecundity_ is also well known as an inherited character. A mother is referred to by Girou,[10] as having had twenty-four children, five of whom, in turn, gave birth to forty-six. A granddaughter of this woman gave birth to sixteen. The females of some families have all or nearly all daughters, who, in turn, have more daughters than sons for several generations. A grandmother had nine daughters, several of whom had no sons in the third generation. _Longevity_ has long been recognized as one of the most transmissible of family traits. _Cæteris paribus_, persons connected with long-lived families have a much more tenacious hold on life than others: the capacity for resisting the changes of climate, the morbific conditions of the atmosphere and soil, the influences of epidemic diseases, and the experiences of privation and hardships, is greater than with other persons; and, conversely, the capacity for resisting these influences is much less with persons whose ancestors have invariably died at an early age. So also if a person resembles in physical form, complexion, and constitution, the ancestors of one side of his family who have lived to old age, while those on the other side have died comparatively young, his prospects of longevity are generally strengthened in proportion to the extent of such resemblance. M. Levy says: "To be born of healthy and strong parents is to have a good chance of longevity; the energy of the constitution is the best buckler against the assault of destructive causes. Rush did not know an octogenarian whose family did not offer many examples of advanced old age. This observation, made by Sinclair, has acquired the force of an axiom, so common is it to meet with longevity as a frequent occurrence among many members of the same family. Inheritance exercises the same influence on the total duration of life of short period: in the Turgot family scarcely a member passed the fiftieth year; he, who rendered it illustrious, died at the age of fifty-three, in spite of the appearance of great vigor of temperament." So familiar to every one are the facts connected with the transmission of morbid physiological processes, that I need not refer to this point further than to remark, that the phthisical, the cancerous, and the scrofulous diatheses are those well known to be more surely inherited, and that through these channels of diseased action whole families cease to exist after two or three generations, unless the tendency is counteracted by more vigorous and healthy influences from the other parent.