This observation of course does not stand alone. I have cited a number of observations and might cite many more in which the same phenomenon of transformation or conversion of sensory images of one sense into images of another sense was prominent. Indeed a study of hallucinations, artificial or spontaneous, which are representations of former experiences and where the determining factors can be ascertained, will show that in most, if not all, of them this same _mechanism of conversion_ is at work. Take, for instance, the experiment cited in our last lecture, the one in which Miss B. was directed to look into a crystal for the purpose of discovering the whereabouts of some money she had lost without being aware of the fact. In the crystal she sees a vision of herself walking along a particular street in Boston absorbed in thought. She sees herself in a moment of absent-mindedness take some banknotes out of her pocket, tear them up, and throw them into the street. Now this artificial hallucination was, as we have seen, a picture of an actual occurrence for which there was amnesia. It must, therefore, have been determined by that experience. The psychological phenomena manifested, however, were really much more complicated than would appear at first sight. An analysis of this vision, which unfolded itself like a cinematograph picture, would show that it was a composite visual representation of several different kinds of experiences—of past perceptions of her body and face, of her conscious knowledge of her relation to the environment (in the street), of muscular movements, and of her knowledge derived from subconscious tactile impressions of the act. Of these last she was not aware at the time of their occurrence. Much of this knowledge must have persisted as a residuum of the original experience and functioned subconsciously. Thereby, perhaps, the original secondary visual images were reproduced and emerged into consciousness as the hallucination or pictorial memory. Similar phenomena indicative of conservation being effected by means of a residuum of the original experience may be produced experimentally in various ways. For instance, in certain hysterics with anesthesia if you prick a number of times a part of the body—say the hand—in which all tactile sensation has been lost, and later direct the subject to look into a crystal, he will see a number, perhaps written on a hand. This number, let us say five, will correctly designate the number of times the hand was pricked. Now, because of the loss of sensibility, the subject was unaware of the pin-pricks. Nevertheless, of course, they were recorded subconsciously, coconsciously). Their subsequent transformation into a visual hallucination not only shows that they were conserved, but that they left something which was capable of taking part, outside of consciousness, in a secondary process which gave rise to the hallucination.