The uniformity of visceral responses when almost any feelings grow very intense, and under such conditions the identity of these responses with those characteristically aroused in the belligerent emotion of anger or rage and its counterpart, fear, offer interesting possibilities of transformation and substitution. This is especially true in the activities of human beings. And because men have devised such terribly ingenious and destructive modes of expressing these feelings in war, an inquiry into the basis for possible substitution seems not out of place. Support for the Militarist Estimate of the Strength of the Fighting Emotions and Instincts The business of killing and of avoiding death has been one of the primary interests of living beings throughout their long history on the earth. It is in the highest degree natural that feelings of hostility often burn with fierce intensity, and then, with astonishing suddenness, that all the powers of the body are called into action--for the strength of the feelings and the quickness of the response measure the chances of survival in a struggle where the issue may be life or death. These are the powerful emotions and the deeply ingrained instinctive reactions which invariably precede combat. They are the emotions and instincts that sometimes seize upon individuals in groups and spread like wildfire into larger and larger aggregations of men, until vast populations are shouting and clamoring for war. To whatever extent military plans are successful in devising a vast machine for attack or defense, the energies that make the machine go are found, in the last analysis, in human beings who, when the time for action comes, are animated by these surging elemental tendencies which assume control of their conduct and send them madly into conflict.