The brain as an organ of mind / by H. Charlton Bastian.

  • Henry Charlton Bastian
Date:
1902
Catalogue details

Licence: In copyright

Credit: The brain as an organ of mind / by H. Charlton Bastian. Source: Wellcome Collection.

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    ataxy’ the amount of symptoms indicative of a diminution in th® so-called ‘ muscular sense ’ was generally proportionate to the im- pairment of the different modes of common sensibility in the limb. Yet some more exceptional cases of this disease recorded by Bazire, Trousseau and others, as well as some remarkable cases referred to by Landry, in which, without the existence of anoesthesiat the patients were reduced to a condition very similar, as regards motility and the sensations resulting from movement, to that of Demeaux’s patient, seemed to show pretty conclusively “ that the brain is assisted in the execution of voluntary movements by guid- ing impressions of some kind, which, whilst they differ in mode of origin from the impressions derivable by means of the ordinary cutaneous and deep sensibility, may differ still further from these, owing to the fact of their not being revealed in consciousness* .... There is clearly a loss of something in these cases, of a something which serves as a guide in the execution of voluntary movements, but whose absence can be compensated by the supervision of the visual sense; and this is in great part the function which some physiologists attach to the ‘ muscular sense ’ my position is that these impressions of the muscular sense, whose existence we are thus obliged to postulate, are unconscious impressions, and that the conscious impressions that have usually been stated to fall within its province are really derivable through modes of ordinary cutaneous and deep sensibility.” The conclusions thus deduced in 1869, are fully borne out by what we now know concerning Hemi-anaesthesia of cerebral origin. The instance recorded by Demeaux is altogether exceptional, since in many of such cases complete superficial, and in some even deep * The route of these afferent inapressions at the commencement and toward* the end of their course was then wholly unknown. And in face of difl&culties presented by evidence adduced by Arnold, the writer hazarded the following conjecture: ” Thus I assume it to be possible that when molecular changes are excited in certain spinal motor cells as a result of a volitional impulse, proportional recurrent impressions may be carried along certain fibres taking origin from the mot)r cells, and ascending in the posterior coltimns of the cord.” In this way the brain might derive impressions referrible to the degree of activity of the various muscles, or sets of muscles, of a hmb. But our present increased knowledge concerning the existence of ‘sensory’ nerves in muscle, no longer renders necessary any such hypothesis, especially as the writer is now inclined to agree with Perrier in his interpretation (‘ Functions of the Brain,’ p. 220) of Arnold’s expertments, H* thus no longer feels any difficulty in believing that some of the sensory fibres of muscles which enter the spinal cord by the posterior roots of the spinal nerves, may transmit to the brain those almost ever-present ‘ unconscious ’ impression* which ■*0 materially guid) u* in the execution of all our movements.