A. Marro.Biology and Eugenics.123 I have added 100 insane of the Manicome of Turin, taken by chance amongst the new entries of 1886, amongst whom I have completed this study. I commenced by classing the age of the parents in three periods, that is to say, immaturity, complete maturity, and decadence. In order to mark the period of immaturity I took as limit the age fixed by legislation after which a man can marry without the consent of his parents, 25 years. I limited the period of perfect development between 26 and 40 years. I marked the period of decadence from 41 years onwards, because oculists admit that presbyopia commences at this age and at this age man has usually a tendency to stoutness, the first indication of the slackening of the vital movement, and as a natural consequence, the decline of the biological powers. Having thus divided parents of the subjects observed by me according to the different ages, my observations have shown that the number of criminals was in excess amongst the descendants of parents either very young or old, compared with what one observed amongst the people living at liberty. This result being obtained, I wished to find out if there existed a conĀ­ nection between the special forms of crime in which the characters of the condemned reveal themselves and the peculiarities of character belonging to the different parental ages at which they had been begotten. The psychical conditions which pre-dispose to criminality consist sometimes in a greater impressionability of character, in consequence of which the mind reacts with great promptitude to the agencies which come to excite it, and offers less resistance to seductions of various kinds which flatter its passions. Sometimes, on the contrary, criminality has its origin in really morbid impulses which take their origin from a condition of depression of mind, from a lack of affectivity or from a delusion of persecution. Now we can recall that the first conditions predisposing to crime are found in conjunction with the state natural to youth. With youth one usually notes an exaltation of feeling which naturally is found united with incapacity of reflection, lack of foresight, and leads easily to indulgence in pleasure, to an aversion to continued and uniform occupations, which most professional work demands, because the powers are not yet well proporĀ­ tioned, and also to inhibitory mental representations, while it lacks power of resisting impressions which arrive at the common sensorium. On the contrary, the qualities which mark depression, melancholy, lack of affectivity and a tendency to delusions of persecution, may a friori be considered as inherited from two aged parents, because in old age the decline of physical forces is reflected upon the moral forces. Man tends to become discontented with everybody; prudence, circumspection, and egotism become more marked with him. To sum up, in his mind there prevails a condition of depression which deprives him of confidence in his