Here, too, we note a certain correlation between the state of discontent, of suspicion, of frigid egoism, which the decline of physical energy tends to arouse in the old, and the absence of affectionate sentiment and a tendency to delusions of persecution which are usual in murderers. Among the insane, moral idiocy in particular, and the degenerative forms in general, appeared more frequently in children of aged parents. As to schoolboys, I have noticed that the minimum of good conduct and the maximum of better developed intelligence coincides with the possession of youth by both parents. The age of complete development corresponds to a maximum of good conduct and a minimum of bad conduct, and retains a large proportion of intelligent children. In the period of decline of both parents, good conduct of children is observed in a smaller proportion than in the preceding period, and high intelligence in a very small proportion. Among biological qualities I have made observations on longevity; among persons of 70 and 80 whom I have examined there is a large proportion of parents who themselves enjoyed remarkably long lives, which proves the transmissibility from father to son of powers of resistance against the stresses of life. Among physical qualities I have made note of the fact that from alcoholic or aged parents were descended children in whom degenerative physical characteristics were most frequently apparent, recalling some features of an inferior human type, such as exaggeration of the frontal sinuses, the torus occipitalis, ears with the Darwinian tubercles prominent, the forehead receding, etc. At the same time the ascendants of those who presented typical and anomalous characters, due to morbid influences of various kinds and following on faulty development of the foetus, such as cretinism, congenital goître, nasal deflections, strabismus, plagio-cephaly, hydrocephaly, dental malformation, etc., showed a large number of alcoholics and epileptics. The explanation of the pernicious consequences to the psycho-physical characters of the children of parents too young or too advanced in age does not present much difficulty. At the younger period the organism is still in process of formation; the incomplete development of the skeleton, as of all the other organs, continually absorbs a mass of plastic materials necessary to the formation of offspring. So we may consider that the faults of children born of too young parents are due to an incomplete development because of the insufficiency of plastic material. We must, on the other hand, seek in the conditions which accompany old age for the reason why it has a disastrous influence on the vitality of the germinal elements of the parents and predisposes the descendants to various forms of physical and moral degeneracy.