Volume 1

The principles of psychology / by Herbert Spencer.

  • Herbert Spencer
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: The principles of psychology / by Herbert Spencer. Source: Wellcome Collection.

    62/670 page 44
    clustering of nervous centres tliat were previously far apart. And there is both a relative and an absolute increase in those centres which have the most multiplied relations with local centres, and through them with all parts of the body. The nervous system is made up of threads inclosed in sheaths, and corpuscles imbedded in protoplasm; of which the threads, united into bundles, constitute almost the whole of the peripheral parts, while the corpuscles with their matrix are found chiefly in the central parts. Having at its outer extremity a plexus of highly-unstable matter, a nerve-thread, consisting as we conclude of less unstable matter but matter isomerically transformed with ease, runs inwards, surrounded by substances that shield it from lateral distur- bance. Eventually it reaches a mass of highly unstable matter, so conditioned as to undergo decomposition with the greatest facility; and from the place where this lies there run other like fibres to other masses of unstable matter, of the same kind, or of a different land, or both—here to a portion of substance that contracts when disturbed, and here to a superior centre containing more of the easily-de- composed nerve-substance. These threads, afferent, efferent, and centripetal, with their connecting corpuscle or portion of grey matter, we regard as forming the unit of composi- tion of the nervous system. Such units are variously grouped and combined. Each local ganglion is a place where many afferent and many efferent nerves are connected by many portions of the un- stable nerve-matter, capable of suddenly giving out much molecular motion. Each superior ganglion is a place where centripetal and centrifugal fibres from such local or inferior ganglia, are similarly connected bv similar matter. And so with still higher ganglia in their relations to these. 1 rom which principle of combination it results that the possibili- ties of different compound relations increase as fast as the centralization progresses. We saw, however, that this establishment of more
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