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346 w. JAMES : first putting on a pair of spectacles, of a doubt whether the field of view draws near or retreats. 1 There is still another deception, occurring in persons who have had one eye-muscle suddenly paralysed. This deception has led Wundt to affirm that the eyeball-feeling proper, the incoming sensation of effected rotation, tells us only of the direction of our eye-movements, but not of their whole extent. 2 For this reason, and because not only Wundt, but many other authors, think the phenomena in these partial paralyses demonstrate the existence of a feeling of inner- vation, a feeling of the outgoing nervous current, opposed to every afferent sensation whatever, it seems proper to note the facts with a certain degree of detail. Suppose a man wakes up some morning with the external rectus muscle of his right eye half-paralysed, what will be the result ? He will be enabled only with great effort to rotate the eye so as to look at objects lying far off to the right. Something in the effort he makes will make him feel as if the object lay much farther to the right than it really is. If the left and sound eye be closed, and he be asked to touch rapidly with his finger an object situated towards his right, he will point the finger to the right of it. The current explanation of the ' something ' in the effort which causes this deception is, that it is the sensation of the outgoing discharge from the nervous centres, the "feeling of innerva- tion," to use Wundt 's expression, requisite for bringing the open eye with its weakened muscle to bear upon the object to be touched. If that object be situated 20 degrees to the right, the patient has now to innervate as powerfully to turn the eye those 20 degrees as formerly he did to turn the eye 30 degrees. He consequently believes as before that he has turned it 30 degrees ; until, by a newly acquired custom, he learns the altered spatial import of all the discharges his brain makes into his right abducens nerve. The " feeling of innervation," maintained to exist by this and other observations, plays an immense part in the space- theories of certain philosophers, especially Wundt. I have elsewhere tried to show that the observations by no means 1 These strange contradictions have been called by Anbert " secondary " deceptions of judgment. See Grundssiige d. Physiologischen Optik, Leipzig, 1876, pp. 601, 615, 627. One of the best examples of them is the small size of the moon as first seen through a telescope. It is larger and brighter, so we see its details more distinctly and judge it nearer. But because we judge it so much nearer we think it must have grown smaller. Cf. Char- pentier in Jahresb. x. 430. 2 Revue Philosophique, iii. 9, p. 220.