But these various timbres of the voice especially contain a not insignificant danger for the criminalist. Whoever once has devoted himself to the study of them trusts them altogether too easily, for even if he has identified them correctly hundreds of times, it still may happen that he is completely deceived by a voice he holds as “characteristically demonstrative.” That timbres may deceive, or simulations worthy of the name occur, I hardly believe. Such deceptions are often attempted and begun, but they demand the entire attention of the person who tries them, and that can be given for only a short time. In the very instant that the matter he is speaking of requires the attention of the speaker, his voice involuntarily falls into that tone demanded by its physical determinants: and the speaker significantly betrays himself through just this alteration. We may conclude that an effective simulation is hardly thinkable. It must, however, be noticed that earlier mistaken observations and incorrect inference at the present moment--substitutions and similar mistakes--may easily mislead. As a corroborative fact, then, the judgment of a voice would have great value; but as a means in itself it is a thing too little studied and far from confirmed. There is, however, another aspect of the matter which manifests itself in an opposite way from voice and gesture. Lazarus calls attention to the fact that the spectators at a fencing match can not prevent themselves from imitative accompaniment of the actions of the fencers, and that anybody who happens to have any swinging object in his hand moves his hand here and there as they do. Stricker[76] makes similar observations concerning involuntary movements performed while looking at drilling or marching soldiers. Many other phenomena of the daily life--as, for example, keeping step with some pedestrian near us, with the movement of a pitcher who with all sorts of twistings of his body wants to guide the ball correctly when it has already long ago left his hand; keeping time to music and accompanying the rhythm of a wagon knocking on cobblestones; even the enforcement of what is said through appropriate gestures when people speak vivaciously--naturally belong to the same class. So do nodding the head in agreement and shaking it in denial; shrugging the shoulders with a declaration of ignorance. The expression by word of mouth should have been enough and have needed no reinforcement through conventional gestures, but the last are spontaneously involuntary accompaniments.