On the necessary conditions of sensations, as illustrated by the sense of hearing / by John G. McKendrick, M.D., F.R.C.P.E.

  • McKendrick, John G. (John Gray), 1841-1926.
Date:
1873
Catalogue details

Licence: Public Domain Mark

Credit: On the necessary conditions of sensations, as illustrated by the sense of hearing / by John G. McKendrick, M.D., F.R.C.P.E. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    ON THE NECESSARY CONDITIONS OF SENSATIONS, AS ILLUSTRATED BY THE SENSE OF HEARING. By JOHN G. M'KENDRICK, M.D., F.R.C.P.E., ASSISTANT TO THE PROFESSOR OP PHYSIOLOGY IN THE UNIVERSITY OF EDINBURGH. Reprinted from the Edinburgh 3Iedical Journal for February 1873. The human mind is conscious of its own existence, and also of the existence without and beyond it, and correlative to it, of a world of matter. The two great facts, mind and matter, are universally recognised, notwithstanding the laborious attempts of different schools of metaphysicians to deny the logical existence of either one or the other. Though we do not know, and may never know, the true nature of either mind or matter, we assume their existence, because we can appreciate certain of their properties either through the medium of the senses or by intellectual processes. If this be granted, we have next to inquire how the mind acquires knowledge of the properties of matter, or of physical phenomena of any kind. Can we separate what is apparently a complicated process into its constituent parts? What are the anatomical and physiological conditions necessary for bringing the subject mind into relation with the object world ? These conditions are:— 1. A sense-organ for the reception of movements of matter, and for the communication of these movements to a nerve. 2. A nerve-centre, or brain, which is the seat of consciousness ; and, 3. A nerve, endowed with a special sensibility peculiar to the sense, for conveying influences from the sense-organ to the brain. It will be found we have these three elements in each sense. With regard to the nerve-centre or brain, there may be a still farther subdivision ; the influence is not transmitted directly to the cerebral hemispheres, the seat of consciousness, but is first received by a subsidiary ganglion, from which it is passed onwards to the hemispheres. For example, as the necessary conditions of the sense of vision in the higher animals, we find (1) a sense-organ, the retina, for receiving certain movements, the undulations of the ether which constitute a ray of light; (2) a nerve, the optic, for