It is thus possible rudely to classify hostilities under three heads, according to the degree of mental organization they involve; namely, as 1. Primary, immediate, or animal. 2. Social, sympathetic, imaginative, or personal, of a comparatively direct sort, that is, without reference to any standard of justice. 3. Rational or ethical; similar to the last but involving reference to a standard of justice and the sanction of conscience. The function of hostility is, no doubt, to awaken a fighting energy, to contribute an emotional motive force to activities of self-preservation or aggrandizement. In its immediate or animal form this is obvious enough. The wave of passion that possesses a fighting dog stimulates and concentrates his energy upon a few moments of struggle in which success or failure may be life or death; and the simple, violent anger of children and impulsive adults is evidently much the same thing. Vital force explodes in a flash of aggression; the mind has no room for anything but the fierce instinct. It is clear that hostility of this uncontrolled sort is proper to a very simple state of society and of warfare, and is likely to be a source of disturbance and weakness in that organized state which calls for corresponding organization in the individual mind. There is a transition by imperceptible degrees from the blind anger that thinks of nothing to the imaginative anger that thinks of persons, and pursues the personal idea into all possible degrees of subtlety and variety. The passion itself, the way we feel when we are angry, does not seem to change much, except, perhaps, in intensity, the change being mostly in the idea that awakens it. It is as if anger were a strong and peculiar flavor which might be taken with the simplest food or the most elaborate, might be used alone, strong and plain, or in the most curious and recondite combinations with other flavors. While it is evident enough that animal anger is one of those instincts that are readily explained as conducive to self-preservation, it is not, perhaps, so obvious that socialized anger has any such justification. I think, however, that, though very liable to be excessive and unmanageable, and tending continually to be economized as the race progresses, so that most forms of it are properly regarded as wrong, it nevertheless plays an indispensable part in life.