The psychology of imitation does not form part of our subject. Baldwin has made an excellent study of it (_Mental Development in the Child and Race_, pp. 263-366). He defines it as "a sensori-motor reaction, which finds its differentia in the single fact that it imitates; that is, its peculiarity is found in the locus of its muscular discharge. It is what I have called a ‘circular activity’ on the bodily side,—brain-state due to stimulating conditions, muscular reaction which reproduces or retains the stimulating conditions,—same brain-state again, due to same stimulating conditions, and so on." Imitation appears early in the child, at fifteen weeks (Preyer) or four months (Darwin). Are we to consider it as an instinct? Popular opinion is inclined to do so, as are also several psychologists—Stricker, James, and others. The contrary is maintained by Preyer, Bain, Sully, and Baldwin—a view I am myself inclined to take. Imitation does not present the true characteristics of an instinct; it is not adapted at the first attempt; it gropes its way, it is tentative, it fails again after success, it retrogrades, or progresses but slowly. It is an ideo-motor reflex; it takes its place above instinct (a blind and innate tendency inferior to the voluntary activity for which it prepares the way), because it is the first attempt at convergence towards an end. It manifests itself in animals forming aggregates (not societies), such as a flock of sheep, or a pack of dogs who run, stop, bark all at the same time, through a purely physical impulse of imitation: in man, infectious laughter or yawning, walking in step, imitating the movements of a rope-walker while watching him, feeling a shock in one’s legs when one sees a man falling, and a hundred other occurrences of this kind are cases of physiological sympathy. It plays a great part in the psychology of crowds, with their rapid attacks and sudden panics. In nervous diseases, there is a superfluity of examples: epidemics of hysteric fits, convulsive barking, hiccup, etc. I omit the mental maladies (epidemics of suicide, double or triple madness) since we are only considering the purely physiological stage. To sum up, sympathy is originally a property of living matter: as there is an organic memory and an organic sensitiveness, being those of the tissues and ultimate elements which compose them, there is an organic sympathy, made up of receptivity and imitative movements. The _second phase_ is that of sympathy in the psychological sense, necessarily accompanied by consciousness; it creates, in two or more individuals, analogous emotional states. Such are the cases in which we say that fear, indignation, joy or sorrow are communicated. It consists in feeling an emotion existing in another, and is revealed to us by its physiological expression. This phase consists of two stages.