In order to overcome the difficulty just mentioned, I selected another subject (Miss von L.), whose power of visualizing was very slight, and requested her to fix her mind upon four words which I had selected because they were not, necessarily, associated with a particular image. The order in which the words were to be thought of, was entirely optional on her part. The words were "Form", "Inhalt", "Mass", and "Zahl", (form, content, measure, and number), and each of them I accompanied, with a certain definite arm movement. The subject always pronounced the word inwardly as emphatically as possible, but without ever imaging the corresponding arm movement. Often, it must be noted, she did not know whether or not the movement which I made was the proper one. And yet she, too, soon fell into line in the matter of executing unconsciously the characteristic head movements. In a total of 50 tests, I was able to make 10 correct guesses in the course of the first 20 tests, 8 in the next 10 tests, and 19 in the last 20 tests. Miss von L. noted only a few of her upward head-movements, viz.: those that were especially pronounced (movements through about 2 millimeters), but of the others she knew nothing. The same experiment was repeated with a psychologist, well-trained in introspection, as a subject. Success was even greater here. But no matter how closely the subject observed himself, he was unable to solve the puzzle. Variations which were introduced in these tests, I will only mention in passing. Thus, instead of making an arm movement, I, in some cases, would tap with my foot, for "Ibis" once, for "Kiebitz" twice. The subject could not see my feet. The involuntary movement-expression which became associated with "Ibis" was one nod of the head, with "Kiebitz" two nods, etc. Here our only concern was to show that unconscious change in natural expressive movements and the acquisition of artificial ones are possible in the case of psychically normal subjects trained in introspection.