Problems of Life and Mind. Second series, George Henry Lewes [e book reading free TXT] 📗
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I was delighted to find my opposition to the current teaching respecting the central functions of ganglionic cells thoroughly borne out by the elaborate researches of Sigmund Mayer (Archiv für Psychiatrie, Bd. VI. Heft 2). Having artificially produced such cells, he pertinently asks, How can we attribute central functions to cells which appear in the process of regeneration of a divided nerve! The error has its origin in the confusion of functions with properties.
88 It is often, though incorrectly, stated that every segment of an annulose animal has its separate ganglion. The fact is, that while the ganglia are usually fewer than the segments, they are sometimes more numerous.
89 It has been proved that the cells of the cornea and the pigment cells of the skin contract under nervous excitation. We cannot suppose that although these are the only cells which have hitherto been brought under experimental observation, they are the only cells subject to nerve-influence. We may safely assume that wherever a nerve-fibre terminates, its action will be transformed into an excitation of the part. Habitually, however, motor-nerves are spoken of as muscle-nerves.
90 On Deduction, see Problems: First Series, Vol. II. p. 159
91 I do not here touch upon the question as to whether these actions of the senses are sensations, because that question demands that we should first settle what is Sensation. I may at once, however, say that what is ordinarily understood as a sensation of color, or a sensation of sound, is, in my opinion, not possible without the cerebrum. But the sensibility of the eye and ear is manifestly preserved.
92 It has been observed that removal of the cerebellum affects the pigment cells of the skin. No doubt other parts are also affected, but the changes have hitherto escaped observation.
93 Owsjannikow describes the results of removing carefully the cranial ganglia of the crayfish; and these effects Meyer observes to be identical with those which follow removal of the large claw of the crayfish! A. B. Meyer, Das Hemmungsnerven-system des Herzens, 1869, p. 23. Let me add that the phenomena described by M. Faivre as following the destruction of one subœsophageal ganglion in the Dytiscus, are so little to be referred to the mere absence of the ganglion, that I find them not to occur when the whole head is removed.
94 Pflüger, Die Sensorischen Funktionen des Rückenmarks,1858. Auerbach, Günzburg’s Zeitschrift. Jahrgang IV. p. 486. Lewes, Leeds Meeting of British Association, 1858, and Physiology of Common Life, 1860.
This recognition of sensation, and even of volition, in spinal actions may be found in the writings of Whytt, Unzer, Prochaska, Legallois, and Mayo; but the establishment of the Reflex Theory had displaced it, and its revival dates from Pflüger.
95 Friedländer (Versuch über die innern Sinne, 1826, I. 77) declares it to be a rational necessity: “Die Annahme eines Nervenfluidums ist Nothwendigkeit der Vernunft.”
96 These terms and the conception they embody were proposed by me in 1859 in a paper “On the necessity of a reform in Nerve-physiology,” read at the Aberdeen meeting of the British Association, and were reproduced in the Physiology of Common Life. (Prof. Owen, probably in forgetfulness of my suggestion, proposed “neuricity.” Lectures on the Comp. Anat. of Vertebrates, 1866, I. p. 318.) The terms were fortunate enough to meet with acceptance from some physiologists both in England and France; and the conception has been more widely accepted than the terms. The most distinguished approver was Prof. Vulpian. “Faute d’une meilleure détermination on peut, avec M. Lewes, donner à la propriété physiologique des fibres nerveuses le nom de neurilité; c’est là ce qui correspondra à la oontractilitè des fibres musculaires.” Leçons sur la physiologie du système nerveux, 1866, p. 220. He also adopted my suggestion (since modified) of Sensibility as the property of ganglionic cells. Compare also Gavarret, Phénomènes physiques de la Vie, 1869, pp. 213 and 222. Taule, Notions sur la nature de la matière organisée, 1866, p. 131. Charles Robin, Anatomie et physiologie cellulaires, 1873, p. 166.
By these channels, and by the German, Italian, Russian, Polish, and Hungarian translations of my work, the suggestions were carried over Europe, crept into scientific journals, and became known to writers who never heard of me. I only mention these facts lest the reader should suppose that my views had been anticipated by certain continental writers.
97 “La force nerveuse n’existe pas comme puissance independant des propriétés de tissu. Elle consiste en l’action des parties excités, sur les parties excitables, l’état de l’excitation des premières agissant comme impression ou stimulation sur les secondes.”—Landry, Traité des Paralysies, 1859, I. 142.
98 “Le système nerveux est tout à la fois l’origine des sensations et l’origine des mouvements. Mais est-ce par une propriété unique, ou par deux propriétés diverses qu’il détermine deux phénomènes aussi distincts!” Flourens, Recherches sur les propriétés et les fonctions du Système Nerveux, 1824, p. 1. He concludes that “la puissance nerveuse n’est pas unique; il n’y a pas une seule propriété, il y en a deux,” p. 24. In this he has been generally followed.
99 “I have raised and stretched the thick orbital nerve of horses on the handle of a scalpel, like a string on the bridge of a violin, without exciting the least sensation; but as soon as mechanical or chemical irritation had given rise to inflammation of the nerve a gentle touch caused violent pain.”—Romberg, Nervous Diseases (translated for the Sydenham Society), I. 10.
100 The experiments of Haller, Sur la nature sensible et irritable des parties, I. 245; and the remarks of Prochaska, De Functionibus Systematis Nervosi (translated by Laycock in the volume published by the Sydenham Society, p. 396), ought to have sufficed. See further on, Chap. V.
101 In mammals about three days, in birds four days, in frogs fourteen to twenty days.
102 Rutherford, in Journal of Anatomy, 1873, No. VIII. p. 331. (Fleischl denies that the nerve in situ has different degrees of reaction. Sitzungsberichte der Wiener Akad., December, 1876.)
103 Munk, in the Archiv für Anat., 1860, p. 798.
104 Haller, Mémoires sur la nature sensible et irritable des parties.
105 Comptes Rendus, 1862, LIV. p. 965.
106 “J’espère vous convaincre que tous les éléments anatomiques des nerfs sensitifs, moteurs, vasomoteurs, et autres, ont les mêmes propriétés, et ne sont distincts que par leurs fonctions. Cette question est de la plus haute importance pour la physiologie générale. C’est celle qui domine toute la physiologie des fibres nerveuses.”—Vulpian, Leçons sur la Physiologie du Système Nerveux, p. 11.
107 Mr. James Andrews.
108 In the second number of La Revue Philosophique, Paris, 1876, I have treated this question of specific energies more at length than I could find space for in the present volume.
109 In 1859 I mentioned that if the nerves of a frog’s back be exposed by raising the skin, they may be pricked or even cut without sensible effect, although a slight prick on the skin will excite the nerves, and cause a reflex action. In 1870, Prof. Fick expressed his astonishment at finding that after he had cut out a piece of the skin, leaving it attached to the body by a single nerve, electrical stimulation of this excised skin caused the frog to make the reflex movement of rubbing the irritated surface; whereas electrical stimulation of the nerve-trunk itself produced no reflex effect, only a twitching of a muscle. Pflüger’s Archiv, 1870, p. 327. Brown Séquard tries to establish a distinct species of nerves as conductors of sensitive impressions, from those which are impressionable. The facts on which he founds these two properties simply show that nerves are so disposed that the stimulus which excites them in one place fails in another. He could hardly maintain that a skin nerve contained impressionable fibres at its periphery, and only conducting fibres in its trunk! See his communication to the Royal Society, Proceedings, 1856; and Lectures in the Lancet, 10th July, 1858.
110 In consequence of this observation some physiologists have maintained that Feeling or Consciousness never arises in cerebral activity, unless the thalami and the connected tracts are at the same time in action. I go further, and maintain that there is no Consciousness (in the restricted meaning of the term) unless the whole organism is involved. Cerebral or spinal activity will be activity of Sensibility; but this is only the basis of Consciousness.
111 “An unconscious sensation, which Lewes distinguishes from perception, is to me an inconceivable (ist für mich ein Unding).”—Schröder van der Kolk, Die Pathologie des Geistes-Krankheiten, p. 22.
112 By selective adaptation is meant the varying combination of motor impulses to suit the varying requirements of the effect to be produced. Physical mechanisms are limited to the performance of definite actions; sensitive mechanisms employ fluctuating combinations of elements in response to fluctuations of stimuli. The wheels, levers, springs, and valves of a machine cannot be differently combined according to varying degrees of the motor-force, as the nerves and muscles of an organism are differently combined by varying sensations. An automaton may be constructed to play on the violin, but it will only play the air to which it is set; it cannot vary the performance,—cannot play a false note, or throw in a crescendo here, a largo there, according to a caprice of feeling. We must admit that violinist has his delicate and changing movements guided by sensations, auditory and muscular; any interruption in the sensations would arrest the movements, which in truth incorporate them. And yet it is well known that the violinist may perform while completely “unconscious.” I do not simply refer to the fact that his thoughts and attention may be elsewhere; I refer to such facts as are recorded in Pathology. Trousseau, for example, had an epileptic patient who was occasionally seized with attacks of complete unconsciousness while he was performing in the orchestra; yet, on reawakening to consciousness, he found that he had continued to play, had kept proper time, and played the proper notes.
113 Claude Bernard, Système Nerveux, 1858, I. 349.
114 Wordsworth, The Prelude.
115 “On peut dire que toujours un phénomène de mouvement reconnait pour point de départ une impression sensitive.”—Claude Bernard, I. 267.
116 Since this was written Prof. Michael Foster and Mr. Dew Smith have published their very important researches on the motions of the heart, which establish
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