We have seen in the last two chapters that there is every reason to believe that, on account of improved external conditions, and notably of the sanitary advances which result from the efforts of preventive medicine, the race is deteriorating in general constitutional robustness. Those selective agencies which in more primitive times destroyed the sickly, especially during their early years of life, have in part been removed or modified, with the result that the sickly are preserved and in larger numbers live through and into the child-bearing period, raising the mean duration of life, but notably increasing the rate of mortality after middle age. These sickly ones leave children behind, who, as a matter of course, transmit their constitution to the race. In our study of disease we included intemperance, for in cases where there is a distinct liability to give way to drunken habits, and apart from those cases where it is merely a habit acquired in bad company, we may look upon it as a symptom of some innate variation from the normal, and it is therefore the physician’s duty to treat it like any other constitutional disease. In the same light we are bound to view the cases of many criminals and persons who from some inborn defect are incapable of doing their share in the work of the community. _Crime is often an Acquired Habit._ It is probable that a large proportion of criminals are the creatures of accident or of vicious training. Children are very imitative, and are apt to acquire the habits and even modes of thought of those who surround them; and bad example in their homes, or the neglect of parents who, perhaps, in their turn had also suffered from bad example and neglect, has often stamped a child’s character for life. At school again, the child is surrounded by influences which often affect him throughout life for good or for evil, and later on he is still susceptible to many evil temptations which may in his case be exceedingly strong. We are therefore all of us a compound of our innate inborn qualities, and those that have been stamped, as it were, upon us by contact with the external world; and we have no right to judge in an off-hand manner of the innate qualities of a criminal without a very extensive knowledge of his upbringing, and of the temptations and influences which have surrounded him. Theft by a person in necessity need by no means imply so vicious a temperament as that of a man who spends his life in getting the better of his less clever neighbours, and enriches himself by the loss of others, as is done in many so-called legitimate ways; and the killing of a man in passion may be done by one who would be incapable of settling an old grudge by taking a mean advantage of an enemy. Again, many criminals are incapables driven to crime through their incapacity; therefore with the incapables let us study them. _The Innate Criminal._