Robbery and burglary are generally counted as crimes of violence, but they should be properly classed under property crimes. Every motive that leads to getting property in illegal ways applies to these crimes. There is added to the regular causes of property crimes the element of danger and adventure which makes a strong appeal to boys and men. I am inclined to think that few mature men have committed one of these crimes, unless they began criminal careers as boys. Such crimes especially appeal to the activity and love of adventure which inhere in every boy. They are committed for the most part by youths who have had almost no chance to get the needed sport and physical experience incident to boyhood. The foot-ball, base-ball, polo or golf player very seldom becomes a robber or a burglar. Almost no rich man or rich man's son becomes a robber or a burglar. Those who fall under this lure are mainly the denizens of the streets, the railroad yards, the vacant lots, the casual workers who are stimulated by a variety of conditions to get property unlawfully. Added to this are almost invariably a defective heredity, vicious environment, little education, and a total want of direction in the building up of habits and inhibitions. The robber or burglar who kills in the commission of crime is more dangerous and harder to cure than the one who kills from passion or malice. There is always the element of an occupation, for getting property, and generally a love of adventure that is difficult to overcome, except by a substantial change of social relations which makes acquiring property easier for the class from which all these criminals develop. The murder that comes from passion and feeling implies situations and circumstances that are rarely strong enough to overcome the restrictions against killing. XIII MAN AS A PREDATORY ANIMAL Not less than eighty per cent of all crimes are property crimes, and it seems probable that, of the rest, most arise from the same motives. If we look at civilization as the result of that seesaw trend of the race from "Naturalism to Artificialism," we may get a flexible view of life that will be in accordance with the facts, and will help us to get rid of the arbitrary division of man's history into the three periods termed Savagery, Barbarism and Civilization. However desirable this division may be for historic purposes in general, it is only confusing in an effort to study the nature of man. In the life and origin of the race, the fact is always evidenced that the Ego through its growth and persistence is always drawing to itself from the current of environment all things which it feels desirable to its life and growth. This must be a necessary condition of survival. In the long journey from amoeba to man, any circumstance causing a complete halt for even a brief period meant extinction, while even a persistent interference produced a weakened organism, if not an arrest of development.