distance from the eye. Again: "_Sensations_ are what we call the impressions on our senses, in so far as they come to our consciousness as states of our own body, especially of our nervous apparatus; we call them _perceptions_ when we form out of them the representation of outer objects." (Helmholtz: Tonempfindungen, 1870, p. 101.)--Once more: "Sensation is always accomplished in the psychic centres, but it manifests itself at the excited part of the periphery. In other words, one is conscious of the phenomenon in the nervous centres,... but one perceives it in the peripheric organs. This phenomenon depends on the experience of the sensations themselves, in which there is a _reflection_ of the subjective phenomenon and a tendency on the part of perception to return as it were to the external cause which has roused the mental state because the latter is connected with the former." (Sergi: Psychologie Physiologique (Paris, 1888), p. 189.)--The clearest and best passage I know is in Liebmann: Der Objective Anblick (1869), pp. 67-72, but it is unfortunately too long to quote. [41] This is proved by Weber's device of causing the head to be firmly pressed against a support by another person, whereupon the direction of traction ceases to be perceived. [42] Lotze: Med. Psych., 428-433; Lipps: Grundtatsachen des Seelenlebens, 582. [43] Injuries to Nerves (Philadelphia, 1872), p. 350 ff. [44] In reality it probably means only a restless movement of desire, which he might make even after he had become aware of his impotence to touch the object. [45] Revue Philosophique, vii. p. 1 ff., an admirable critical article, in the course of which M. Janet gives a bibliography of the cases in question. See also Dunan: _ibid._ xxv. 165-7. They are also discussed and similarly interpreted by T. K. Abbot: Sight and Touch (1864), chapter x. [46] The intermediary and shortened locations of the lost hand and foot in the amputation cases also show this. It is easy to see why the phantom foot might continue to follow the position of the artificial one. But I confess that I cannot explain its half way-positions.