The expression “physical” in reference to the dream, which owes its prominence to this author, points in more than one direction. In the first place, it refers to the etiology of the dream, which was especially clear to Binz, as he studied the experimental production of dreams by the administration of poisons. It is certainly in keeping with this kind of dream theory to ascribe the incitement of the dream exclusively to somatic origin whenever possible. Presented in the most extreme form, it reads as follows: After we have put ourselves to sleep by removing the stimuli, there would be no need and no occasion for dreaming until morning, when the gradual awakening through the incoming stimuli would be reflected in the phenomenon of dreaming. But as a matter of fact, it is not possible to keep sleep free from stimuli; just as Mephisto complains about the germs of life, so stimuli reach the sleeper from every side—from without, from within, and even from certain bodily regions which never give us any concern during the waking state. Thus sleep is disturbed; the mind is aroused, now by this, now by that little thing, and functionates for a while with the awakened part only to be glad to fall asleep again. The dream is a reaction to the stimulus causing a disturbance of sleep—to be sure, it is a purely superfluous reaction. To designate the dream as a physical process, which for all that remains an activity of the mental organ, has still another sense. It is meant to dispute the dignity of a psychic process for the dream. The application to the dream of the very old comparison of the “ten fingers of a musically ignorant person running over the keyboard of an instrument,” perhaps best illustrates in what estimation the dream activity has been held by the representatives of exact science. In this sense it becomes something entirely untranslatable, for how could the ten fingers of an unmusical player produce any music? The theory of partial wakefulness has not passed without objection even in early times. Thus Burdach,[8] in 1830, says: “If we say that the dream is a partial wakefulness, in the first place, we explain thereby neither the waking nor the sleeping state; secondly, this expresses nothing more than that certain forces of the mind are active in the dream while others are at rest. But such irregularities take place throughout life....” (p. 483).