On certain disorders and defects of memory / by Thomas Laycock, M.D.

  • Laycock, Thomas, 1812-1876.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: On certain disorders and defects of memory / by Thomas Laycock, M.D. 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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    knowledge, tend to evolve and develop as certainly as a seed or an egg, so that tlicy are in nowise merely material. I have repeatedly indicated these characteristics—first, in an appendix to my paper on the Keflex Function of the Brain, read to the British Association for the Advancement of Science, at its meeting at York in 1844, and published in the British and Foreign Medical Review, January 1845 ; and next, in my review of Unzer's Erste Griinde, when I specially pointed out their relations to external impressions, and how tiiey difltered-from the material ideas of metaphysicians and physiologists; observing that these substrata were due to certain changes in the molecular arrangement or constitution of the neurine induced by frequently recurring impressions communicated from without, and corresponding to these impressions and to none other. ^ The acquisition of a song and a tune is an illustration of this process. In 1855 I again explained the meaning of the term, and sliowed how the substrata have special evolutional properties :— By the term psychical substrata 1 do not mean to imply a certain ma- terial arranger^ent of cells or their elements only, but such an arrangement tliat a fixed order of successional changes or plan of action may be impressed upon them. Thus, every primordial or embryonic cell has its psychal sub- strata, in virtue of which there is a continuous series of successional changes, in a iixed, predetermined order, and according to a lixed plan [constituting evolution]. So also in the cell-masses (or vesicular neurine), appropriate to special ideas, tliere are psychal substrata, in virtue of which there is a con- stant construction of new cells, corresponding to those new states of con- sciousness comprised under the general phrase development of ideas, the ideas being developed, and the new cells constructed, according to a fixed and predetermined law of development (or evolution). The substrata have [like primordial cells] potential properties—that is to say, they contain the elements of further and indefinite series of future changes, as well as properties in actual use in relation to the external world. ^ It is absolutely essential to practical ends that the true nature of the organic basis of memory should be understood to be something more than a physical mechanism, like a muscle, or a merely mechani- cal arrangement of cells and fibrils, the numbers of which may be counted and reckoned as so many acquisitions. This is an old. anatomical and physiological doctrine, taught by Hartley, Bonnet, Hooke, Haller, and others, and by Akenside poetically, and which has been recently revived by Professor Bain.^ Looking at each synesis as the last evolution of the brains at the moment it occurs, we must necessarily connect each successive mnemonic evolution with those which have preceded it. This is the law of associated continuity, and is that which underlies all the theories of evolution of whatever kind they may be. The descent of ^ Review of Unzer's Principles of Animal Physiology. Brifish and Foreign Medical Review, July 1847, p. 186. 2 Further Researches into the Functions of the Brain. By Thos. Laycock, M.D., etc. British and Foreign ]\ledico-Chirurgical Review, July 1855, p. 187. 8 Mind and Body. 1874, p. 107. ' ^ ' i