The writer of this note has determined the proportion of each century in which the leading nations have been engaged in war. The curve thus found has no great reliability; for it does not take into account the percentages of the peoples concerned, but its course clearly indicates that even under circumstances as they have been, wars will come to an end. And there is good reason to believe that the newer condition--universal education and universal suffrage, democratic control, improved economic conditions of living for the people, the scientific attitude--will tend to bend the curve more rapidly toward the base line of permanent "peace on earth and good will to men." While man has inherited instincts which exhibit themselves in playing and fighting, the same instincts may by social control be diverted to playing the games of art or science, to fighting disease and vice. It is rarely wise or feasible to attempt to suppress instincts; they should be directed so as to provide desirable conduct. Loyalty to family, to group, to neighborhood and to nation can not be lightly cast away for an abstract cosmopolitanism. But it can be expressed otherwise than by seizing everything in sight by cunning or by violence. William James, the great psychologist, in one of his brilliant essays published in The Popular Science Monthly for October, 1910, tells us that history is a bath of blood; we inherit the war-like type; our ancestors have bred pugnacity into our bone and marrow; showing the irrationality and horror of war does not prevent it; but a moral equivalent can be found by enlisting an army to toil and suffer pain in doing the hard and routine work of the world. It is doubtful, however, if the "gilded youths" to whom James refers would accept "dish-washing, clothes-washing and window-washing, road-building and tunnel-making, foundries and stoke-holes," as a substitute for war, and for the great mass of the people there is more than enough of these things. It is to escape from them that we seek excitement and adventure, intoxication by drugs and war.