A deaf-mute, who had not been instructed, explained to Romanes, at a later period when he had learned the sign-language, that he had before thought in "images," which means nothing else than that he, in place of the words heard (in our case) and the digital signs seen (in his case), had made use of memory-images gained from visual impressions, for distinguishing his concepts. Laura Bridgman, too, a person in general the subject of very incorrect inferences, who was not blind and deaf from birth, could form a small number of concepts that were above the lowest grade. These originated from the materials furnished by the sense of touch, the muscular sense and general sensibility, before she had learned a sort of finger-language. But she had learned to speak somewhat before she became dumb and blind. Children with sight, born deaf, seem not to be able to perform the simplest arithmetical operations, e. g., 214-96 and 908 X 70 (according to Asch, 1865), until after several years of continuous instruction in articulate speaking. They do succeed, however, and that without sound-images of words, and perhaps, too, without sight-images of words; in mental arithmetic without knowledge of written figures, by help of the touch-images of words which the tongue furnishes. In any case uneducated persons born deaf can count by means of the fingers without the knowledge of figures; and, when they go beyond 10, the notched stick comes to their aid (Sicard and Degerando). The language of gesture and feature in very young children, born dumb and not treated differently from other children, shows also, in most abundant measure, that concepts are formed without words. The child born deaf uses the primitive language of gesture to the same extent as does the child that has his hearing; the former makes himself intelligible by actions and sounds as the latter does, so that his deficiency is not suspected. This natural language is also _understood_ by the child born deaf, so far as it is recognizable by his eye. In the look and the features of his mother he reads her mood. But he very early becomes quiet and develops for himself, "out of unconscious gesticulation, the gesture language, which at first is not conventional, nay, is not in the strict sense quite a sign-language, but a mimetic-plastic representation of the influences experienced from the external world," since the deaf-mute imitates movements perceived, and the attitude of persons and the position of objects. Upon this pantomime alone rests the possibility of coming to an understanding, within a certain range, with deaf-mutes that have had no instruction at all. It can not, therefore, in its elementary form be conventional, as Hill, to whom I owe these data, rightly maintains. He writes concerning the child born deaf: "His voice seems just like that of other children. He screams, weeps, according as he feels uncomfortable; he starts when frightened by any noise. Even