1. The principle of direct modification of innervation—that is to say, that the intensity of the muscular and vasomotor movements depends on the intensity of the emotions; the movements which most escape the control of the will more especially depend on this principle. This is the equivalent to Darwin’s third principle, placed first, which is, in fact, its right position. 2. The principle of the association of analogous sensations consists in those dispositions of the mind which are analogous to certain sensory impressions, manifesting themselves in the same manner. At the outset, we have only pleasures, pains, and needs of the physical order, whose mode of expression is innate, and, so to speak, anatomical. Later on come the pleasures, pains, and desires of the moral order, which make use of the pre-existent modes of expression in order to show themselves outwardly. It is a language turned aside from its primary signification, which in the order of gestures is the equivalent of a metaphor. This principle explains much more easily than Darwin’s a number of apparently very perplexing modes of expression. If a man, when puzzled, scratches his head, coughs, rubs his eyes, it is because a slight _malaise_ of physical origin and a slight embarrassment of psychical origin have a deep-seated analogy, betraying themselves by the same expressive movements. Wundt has well described the mimicry of the mouth in the tasting of sweet, acid, or bitter substances; as soon as an emotion arises which has some affinity with these gustatory sensations (sweet joy, bitter grief, sharp reproaches), the expression of the mouth, the nose, the face reappears. This is because, in both cases, the state of the feelings, the emotional tone are the same, the expressive movements identical. As Mantegazza has rightly said, there are such things as mimic synonyms.