[4]It should be said that this particular cut commonly proves fatal. The text refers to the rare cases which survive.
[4]It should be said that this particular cut commonly proves fatal. The text refers to the rare cases which survive.
[5]I confine myself to the frog for simplicity's sake. In higher animals, especially the ape and man, it would seem as if not only determinate combinations of muscles, but limited groups or even single muscles could be innervated from the hemispheres.
[5]I confine myself to the frog for simplicity's sake. In higher animals, especially the ape and man, it would seem as if not only determinate combinations of muscles, but limited groups or even single muscles could be innervated from the hemispheres.
[6]I hope that the reader will take no umbrage at my so mixing the physical and mental, and talking of reflex acts and hemispheres and reminiscences in the same breath, as if they were homogeneous quantities and factors of one causal chain. I have done so deliberately; for although I admit that from the radically physical point of view it is easy to conceive of the chain of events amongst the cells and fibres as complete in itself, and that whilst so conceiving it one need make no mention of 'ideas,' I yet suspect that point of view of being an unreal abstraction. Reflexes in centres may take place even where accompanying feelings or ideas guide them. In another chapter I shall try to show reasons for not abandoning this common-sense position; meanwhile language lends itself so much more easily to the mixed way of describing, that I will continue to employ the latter. The more radical-minded reader can always read 'ideational process' for 'idea.'
[6]I hope that the reader will take no umbrage at my so mixing the physical and mental, and talking of reflex acts and hemispheres and reminiscences in the same breath, as if they were homogeneous quantities and factors of one causal chain. I have done so deliberately; for although I admit that from the radically physical point of view it is easy to conceive of the chain of events amongst the cells and fibres as complete in itself, and that whilst so conceiving it one need make no mention of 'ideas,' I yet suspect that point of view of being an unreal abstraction. Reflexes in centres may take place even where accompanying feelings or ideas guide them. In another chapter I shall try to show reasons for not abandoning this common-sense position; meanwhile language lends itself so much more easily to the mixed way of describing, that I will continue to employ the latter. The more radical-minded reader can always read 'ideational process' for 'idea.'
[7]I shall call it hereafter for shortness 'the Meynert scheme;' for the child-and-flame example, as well as the whole general notion that the hemispheres are a supernumerary surface for the projection and association of sensations and movements natively coupled in the centres below, is due to Th. Meynert, the Austrian anatomist. For a popular account of his views, see his pamphlet 'Zur Mechanik des Gehirnbaues,' Vienna, 1874. His most recent development of them is embodied in his 'Psychiatry,' a clinical treatise on diseases of the forebrain, translated by B. Sachs, New York, 1885.
[7]I shall call it hereafter for shortness 'the Meynert scheme;' for the child-and-flame example, as well as the whole general notion that the hemispheres are a supernumerary surface for the projection and association of sensations and movements natively coupled in the centres below, is due to Th. Meynert, the Austrian anatomist. For a popular account of his views, see his pamphlet 'Zur Mechanik des Gehirnbaues,' Vienna, 1874. His most recent development of them is embodied in his 'Psychiatry,' a clinical treatise on diseases of the forebrain, translated by B. Sachs, New York, 1885.
[8]Geschichte des Materialismus, 2d ed., ii, p. 345.
[8]Geschichte des Materialismus, 2d ed., ii, p. 345.
[9]West Riding Asylum Reports, 1876, p. 267.
[9]West Riding Asylum Reports, 1876, p. 267.
[10]For a thorough discussion of the various objections, see Ferrier's 'Functions of the Brain,' 2d ed., pp. 227-234, and François-Franck's 'Leçons sur les Fonctions Motrices du Cerveau' (1887), Leçon 31. The most minutely accurate experiments on irritation of cortical points are those of Paneth, in Pflüger's Archiv, vol 37, p. 528.—Recently the skull has been fearlessly opened by surgeons, and operations upon the human brain performed, sometimes with the happiest results. In some of these operations the cortex has been electrically excited for the purpose of more exactly localizing the spot, and the movements first observed in dogs and monkeys have then been verified in men.
[10]For a thorough discussion of the various objections, see Ferrier's 'Functions of the Brain,' 2d ed., pp. 227-234, and François-Franck's 'Leçons sur les Fonctions Motrices du Cerveau' (1887), Leçon 31. The most minutely accurate experiments on irritation of cortical points are those of Paneth, in Pflüger's Archiv, vol 37, p. 528.—Recently the skull has been fearlessly opened by surgeons, and operations upon the human brain performed, sometimes with the happiest results. In some of these operations the cortex has been electrically excited for the purpose of more exactly localizing the spot, and the movements first observed in dogs and monkeys have then been verified in men.
[11]J. Loeb: Beiträge zur Physiologie des Grosshirns; Pflüger's Archiv, xxxix, 293. I simplify the author's statement.
[11]J. Loeb: Beiträge zur Physiologie des Grosshirns; Pflüger's Archiv, xxxix, 293. I simplify the author's statement.
[12]Goltz: Pflüger's Archiv, xlii, 419.
[12]Goltz: Pflüger's Archiv, xlii, 419.
[13]'Hemiplegia' means one-sided palsy.
[13]'Hemiplegia' means one-sided palsy.
[14]Philosophical Transactions, vol. 179, pp. 6, 10 (1888). In a later paper (ibid.p. 205) Messrs. Beevor and Horsley go into the localization still more minutely, showing spots from which single muscles or single digits can be made to contract.
[14]Philosophical Transactions, vol. 179, pp. 6, 10 (1888). In a later paper (ibid.p. 205) Messrs. Beevor and Horsley go into the localization still more minutely, showing spots from which single muscles or single digits can be made to contract.
[15]Nothnagel und Naunyn; Die Localization in den Gehirnkrankheiten (Wiesbaden, 1887), p. 34.
[15]Nothnagel und Naunyn; Die Localization in den Gehirnkrankheiten (Wiesbaden, 1887), p. 34.
[16]An accessible account of the history of our knowledge of motor aphasia is in W. A. Hammond's 'Treatise on the Diseases of the Nervous System,' chapter vii.
[16]An accessible account of the history of our knowledge of motor aphasia is in W. A. Hammond's 'Treatise on the Diseases of the Nervous System,' chapter vii.
[17]The history up to 1885 may be found in A. Christiani: Zur Physiologie des Gehirnes (Berlin, 1885).
[17]The history up to 1885 may be found in A. Christiani: Zur Physiologie des Gehirnes (Berlin, 1885).
[18]Pflüger's Archiv, vol. 44, p. 176. Munk (Berlin Academy Sitzsungberichte, 1889, xxxi) returns to the charge, denying the extirpations of Schrader to be complete: "Microscopic portions of theSehsphäremust remain."
[18]Pflüger's Archiv, vol. 44, p. 176. Munk (Berlin Academy Sitzsungberichte, 1889, xxxi) returns to the charge, denying the extirpations of Schrader to be complete: "Microscopic portions of theSehsphäremust remain."
[19]A. Christiani; Zur Physiol. d. Gehirnes (Berlin, 1885), chaps. ii, iii, iv, H. Munk: Berlin Akad. Stzgsb. 1884, xxiv.
[19]A. Christiani; Zur Physiol. d. Gehirnes (Berlin, 1885), chaps. ii, iii, iv, H. Munk: Berlin Akad. Stzgsb. 1884, xxiv.
[20]Luciani und Seppili: Die Functions-Localization auf der Grosshirnrinde (Deutsch von Fraenkel), Leipzig, 1886, Dogs M, N, and S. Goltz in Pflüger's Archiv, vol. 34, pp. 490-6; vol. 42, p. 454. Cf. also Munk: Berlin Akad. Stzgsb. 1886, vii, viii, pp. 113-121, and Loeb: Pflüger's Archiv, vol. 39, p. 337.
[20]Luciani und Seppili: Die Functions-Localization auf der Grosshirnrinde (Deutsch von Fraenkel), Leipzig, 1886, Dogs M, N, and S. Goltz in Pflüger's Archiv, vol. 34, pp. 490-6; vol. 42, p. 454. Cf. also Munk: Berlin Akad. Stzgsb. 1886, vii, viii, pp. 113-121, and Loeb: Pflüger's Archiv, vol. 39, p. 337.
[21]Berlin Akad. Sitzungsberichte, 1886, vii, viii, p. 124.
[21]Berlin Akad. Sitzungsberichte, 1886, vii, viii, p. 124.
[22]H. Munk: Functionen der Grosshirnrinde (Berlin, 1881), pp. 36-40. Ferrier: Functions, etc., 2d ed., chap, ix, pt. i. Brown and Schaefer, Philos. Transactions, vol. 179, p. 321. Luciani u. Seppili, op. cit. pp. 131-138. Lannegrace found traces of sight with both occipital lobes destroyed, and in one monkey even when angular gyri and occipital lobes were destroyed altogether. His paper is in the Archives de Médecine Expérimentale for January and March, 1889. I only know it from the abstract in the Neurologisches Centralblatt, 1889, pp. 108-420. The reporter doubts the evidence of vision in the monkey. It appears to have consisted in avoiding obstacles and in emotional disturbance in the presence of men.
[22]H. Munk: Functionen der Grosshirnrinde (Berlin, 1881), pp. 36-40. Ferrier: Functions, etc., 2d ed., chap, ix, pt. i. Brown and Schaefer, Philos. Transactions, vol. 179, p. 321. Luciani u. Seppili, op. cit. pp. 131-138. Lannegrace found traces of sight with both occipital lobes destroyed, and in one monkey even when angular gyri and occipital lobes were destroyed altogether. His paper is in the Archives de Médecine Expérimentale for January and March, 1889. I only know it from the abstract in the Neurologisches Centralblatt, 1889, pp. 108-420. The reporter doubts the evidence of vision in the monkey. It appears to have consisted in avoiding obstacles and in emotional disturbance in the presence of men.
[23]Localization of Cerebral Disease (1878), pp. 117-8.
[23]Localization of Cerebral Disease (1878), pp. 117-8.
[24]For cases see Flechsig: Die Leitungsbahnen in Gehirn u. Rückenmark (Leipzig, 1876), pp. 112, 272; Exner's Untersuchungen, etc., p. 83; Ferrier's Localization, etc., p. 11; François-Franck's Cerveau Moteur, p. 63, note.
[24]For cases see Flechsig: Die Leitungsbahnen in Gehirn u. Rückenmark (Leipzig, 1876), pp. 112, 272; Exner's Untersuchungen, etc., p. 83; Ferrier's Localization, etc., p. 11; François-Franck's Cerveau Moteur, p. 63, note.
[25]E. C. Seguin: Hemianopsia of Cerebral Origin, in Journal of Nervous and Mental Disease, vol. xiii, p. 30. Nothnagel und Naunyn: Ueber die Localization der Gehirnkrankheiten (Wiesbaden, 1887), p. 16.
[25]E. C. Seguin: Hemianopsia of Cerebral Origin, in Journal of Nervous and Mental Disease, vol. xiii, p. 30. Nothnagel und Naunyn: Ueber die Localization der Gehirnkrankheiten (Wiesbaden, 1887), p. 16.
[26]Die Seelenblindheit, etc., p. 51 ff. The mental blindness was in this woman's case moderate in degree.
[26]Die Seelenblindheit, etc., p. 51 ff. The mental blindness was in this woman's case moderate in degree.
[27]Archiv f. Psychiatrie, vol. 21, p. 222.
[27]Archiv f. Psychiatrie, vol. 21, p. 222.
[28]Nothnagel (loc. cit.p. 22) says: "Dies trifft aber nicht zu." He gives, however, no case in support of his opinion that double-sided cortical lesion may make one stone-blind and yet not destroy one's visual images; so that I do not know whether it is an observation of fact or ana prioriassumption.
[28]Nothnagel (loc. cit.p. 22) says: "Dies trifft aber nicht zu." He gives, however, no case in support of his opinion that double-sided cortical lesion may make one stone-blind and yet not destroy one's visual images; so that I do not know whether it is an observation of fact or ana prioriassumption.
[29]In a case published by C. S. Freund: Archiv f. Psychiatrie, vol. xx, the occipital lobes were injured, but their cortex was not destroyed, on both sides. There was still vision. Cf.pp. 291-5.
[29]In a case published by C. S. Freund: Archiv f. Psychiatrie, vol. xx, the occipital lobes were injured, but their cortex was not destroyed, on both sides. There was still vision. Cf.pp. 291-5.
[30]I say 'need,' for I do not of course deny thepossiblecoexistence of the two symptoms. Many a brain-lesion might block optical associations and at the same time impair optical imagination, without entirely stopping vision. Such a case seems to have been the remarkable one from Charcot which I shall give rather fully in the chapter on Imagination.
[30]I say 'need,' for I do not of course deny thepossiblecoexistence of the two symptoms. Many a brain-lesion might block optical associations and at the same time impair optical imagination, without entirely stopping vision. Such a case seems to have been the remarkable one from Charcot which I shall give rather fully in the chapter on Imagination.
[31]Freund (in the article cited above 'Ueber optische Aphasie und Seelenblindheit') and Bruns ('Ein Fall von Alexie,' etc., in the Neurologisches Centralblatt for 1888, pp. 581, 509) explain their cases by broken-down conduction. Wilbrand, whose painstaking monograph on mental blindness was referred to a moment ago, gives none buta priorireasons for his belief that the optical 'Erinnerungsfeld' must be locally distinct from the Wahrnehmungsfeld (cf.pp. 84,93). Thea priorireasons are really the other way. Mauthner ('Gehirn u. Auge' (1881), p. 487 ff.) tries to show that the 'mental blindness' of Munk's dogs and apes after occipital mutilation was not such, but real dimness of sight. The best case of mental blindness yet reported is that by Lissauer, as above. The reader will also do well to read Bernard: De l'Aphasie (1885) chap. v; Ballet: Le Langage Intérieur (1886), chap. viii; and Jas. Boss's little book on Aphasia (1887), p. 74.
[31]Freund (in the article cited above 'Ueber optische Aphasie und Seelenblindheit') and Bruns ('Ein Fall von Alexie,' etc., in the Neurologisches Centralblatt for 1888, pp. 581, 509) explain their cases by broken-down conduction. Wilbrand, whose painstaking monograph on mental blindness was referred to a moment ago, gives none buta priorireasons for his belief that the optical 'Erinnerungsfeld' must be locally distinct from the Wahrnehmungsfeld (cf.pp. 84,93). Thea priorireasons are really the other way. Mauthner ('Gehirn u. Auge' (1881), p. 487 ff.) tries to show that the 'mental blindness' of Munk's dogs and apes after occipital mutilation was not such, but real dimness of sight. The best case of mental blindness yet reported is that by Lissauer, as above. The reader will also do well to read Bernard: De l'Aphasie (1885) chap. v; Ballet: Le Langage Intérieur (1886), chap. viii; and Jas. Boss's little book on Aphasia (1887), p. 74.
[32]For a case see Wernicke's Lehrb. d. Gehirnkrankheiten, vol. ii, p. 554 (1881).
[32]For a case see Wernicke's Lehrb. d. Gehirnkrankheiten, vol. ii, p. 554 (1881).
[33]The latest account of them is the paper 'Über die optischen Centren u. Bahnen' by von Monakow in the Archiv für Psychiatrie, vol. xx, p. 714.
[33]The latest account of them is the paper 'Über die optischen Centren u. Bahnen' by von Monakow in the Archiv für Psychiatrie, vol. xx, p. 714.
[34]Die Functions-Localization, etc., Dog X; see also p. 161.
[34]Die Functions-Localization, etc., Dog X; see also p. 161.
[35]Philos. Trans., vol. 179, p. 312.
[35]Philos. Trans., vol. 179, p. 312.
[36]Brain, vol. xi, p. 10.
[36]Brain, vol. xi, p. 10.
[37]Ibid.p. 147.
[37]Ibid.p. 147.
[38]Der aphasische Symptomencomplex (1874). See in Fig. 11 the convolution markedWernicke.
[38]Der aphasische Symptomencomplex (1874). See in Fig. 11 the convolution markedWernicke.
[39]'The Pathology of Sensory Aphasia,' 'Brain,' July, 1889.
[39]'The Pathology of Sensory Aphasia,' 'Brain,' July, 1889.
[40]Nothnagel und Naunyn;op. cit.plates.
[40]Nothnagel und Naunyn;op. cit.plates.
[41]Ballet's and Bernard's works cited onp. 51are the most accessible documents of Charcot's school. Bastian's book on the Brain as an Organ of Mind (last three chapters) is also good.
[41]Ballet's and Bernard's works cited onp. 51are the most accessible documents of Charcot's school. Bastian's book on the Brain as an Organ of Mind (last three chapters) is also good.
[42]For details, see Ferrier's 'Functions,' chap. ix, pt. iii, and Chas. K. Mills: Transactions of Congress of American Physicians and Surgeons, 1888, vol. i, p. 278.
[42]For details, see Ferrier's 'Functions,' chap. ix, pt. iii, and Chas. K. Mills: Transactions of Congress of American Physicians and Surgeons, 1888, vol. i, p. 278.
[43]Functions of the Brain, chap. x, § 14.
[43]Functions of the Brain, chap. x, § 14.
[44]Ueber die Functionen d. Grosshirnrinde (1881), p. 50.
[44]Ueber die Functionen d. Grosshirnrinde (1881), p. 50.
[45]Lezioni di Fisiologia sperimentale sul sistema nervoso encefalico (l. 73), p. 527 ff. Also 'Brain,' vol. ix, p. 298.
[45]Lezioni di Fisiologia sperimentale sul sistema nervoso encefalico (l. 73), p. 527 ff. Also 'Brain,' vol. ix, p. 298.
[46]Bechterew (Pflüger's Archiv, vol. 35, p. 137) foundnoanæsthesia in a cat with motor symptoms from ablation of sigmoid gyrus. Luciani got hyperæsthesia coexistent with cortical motor defect in a dog, by simultaneously hemisecting the spinal cord (Luciani u. Seppili,op. cit.p. 234). Goltz frequently found hyperæsthesia of the whole body to accompany motor defect after ablation of both frontal lobes, and he once found it after ablating the motor zone (Pflüger's Archiv, vol. 34, p. 471).
[46]Bechterew (Pflüger's Archiv, vol. 35, p. 137) foundnoanæsthesia in a cat with motor symptoms from ablation of sigmoid gyrus. Luciani got hyperæsthesia coexistent with cortical motor defect in a dog, by simultaneously hemisecting the spinal cord (Luciani u. Seppili,op. cit.p. 234). Goltz frequently found hyperæsthesia of the whole body to accompany motor defect after ablation of both frontal lobes, and he once found it after ablating the motor zone (Pflüger's Archiv, vol. 34, p. 471).
[47]Philos. Transactions, vol. 179, p. 20 ff.
[47]Philos. Transactions, vol. 179, p. 20 ff.
[48]Functions, p. 375.
[48]Functions, p. 375.
[49]Pp. 15-17.
[49]Pp. 15-17.
[50]Luciani u. Seppili,op. cit.pp. 275-288.
[50]Luciani u. Seppili,op. cit.pp. 275-288.
[51]Op. cit.p. 18.
[51]Op. cit.p. 18.
[52]Trans. of Congress, etc., p. 272.
[52]Trans. of Congress, etc., p. 272.
[53]See Exner's Unters. üb. Localization, plate xxv.
[53]See Exner's Unters. üb. Localization, plate xxv.
[54]Cf. Ferrier's Functions, etc., chap. iv, and chap. x, §§ 6 to 9.
[54]Cf. Ferrier's Functions, etc., chap. iv, and chap. x, §§ 6 to 9.
[55]Op. cit.p. 17.
[55]Op. cit.p. 17.
[56]E.g. Starr,loc. cit.p. 272; Leyden, Beiträge zur Lehre v. d. Localization im Gehirn (1888), p. 72.
[56]E.g. Starr,loc. cit.p. 272; Leyden, Beiträge zur Lehre v. d. Localization im Gehirn (1888), p. 72.
[57]Bernard,op. cit.p. 84.
[57]Bernard,op. cit.p. 84.
[58]Philos. Trans., vol. 179, p. 3.
[58]Philos. Trans., vol. 179, p. 3.
[59]Trans. of Congress of Am. Phys. and Surg. 1888, vol. i, p. 343. Beevor and Horsley's paper on electric stimulation of the monkey's brain is the most beautiful work yet done for precision. See Phil. Trans., vol. 179, p. 205, especially the plates.
[59]Trans. of Congress of Am. Phys. and Surg. 1888, vol. i, p. 343. Beevor and Horsley's paper on electric stimulation of the monkey's brain is the most beautiful work yet done for precision. See Phil. Trans., vol. 179, p. 205, especially the plates.
[60]Pflüger's Archiv, vol. 37, p. 523 (1885).
[60]Pflüger's Archiv, vol. 37, p. 523 (1885).
[61]By Luys in his generally preposterous book 'The Brain'; also by Horsley.
[61]By Luys in his generally preposterous book 'The Brain'; also by Horsley.
[62]C. Mercier: The Nervous System and the Mind, p. 124.
[62]C. Mercier: The Nervous System and the Mind, p. 124.
[63]The frontal lobes as yet remain a puzzle. Wundt tries to explain them as an organ of 'apperception' (Grundzüge d. Physiologischen Psychologie, 3d ed., vol. i, p. 233 ff.), but I confess myself unable to apprehend clearly the Wundtian philosophy so far as this word enters into it, so must be contented with this bare reference.—Until quite recently it was common to talk of an 'ideational centre' as of something distinct from the aggregate of other centres. Fortunately this custom is already on the wane.
[63]The frontal lobes as yet remain a puzzle. Wundt tries to explain them as an organ of 'apperception' (Grundzüge d. Physiologischen Psychologie, 3d ed., vol. i, p. 233 ff.), but I confess myself unable to apprehend clearly the Wundtian philosophy so far as this word enters into it, so must be contented with this bare reference.—Until quite recently it was common to talk of an 'ideational centre' as of something distinct from the aggregate of other centres. Fortunately this custom is already on the wane.
[64]Rech. Exp. sur le Fonctionnement des Centres Psycho-moteurs (Brussels, 1885).
[64]Rech. Exp. sur le Fonctionnement des Centres Psycho-moteurs (Brussels, 1885).
[65]Pflüger's Archiv, vol. 44, p. 544.
[65]Pflüger's Archiv, vol. 44, p. 544.
[66]I ought to add, however, that François-Franck (Fonctions Motrices, p. 370) got, in two dogs and a cat, a different result from this sort of 'circumvallation.'
[66]I ought to add, however, that François-Franck (Fonctions Motrices, p. 370) got, in two dogs and a cat, a different result from this sort of 'circumvallation.'
[67]For this word, see T. K. Clifford's Lectures and Essays (1879), vol. ii, p. 72.
[67]For this word, see T. K. Clifford's Lectures and Essays (1879), vol. ii, p. 72.
[68]See below,Chapter VIII.
[68]See below,Chapter VIII.
[69]Cf. Ferrier's Functions, pp. 120, 147, 414. See also Vulpian: Leçons sur la Physiol. du Syst. Nerveux, p. 548; Luciani u. Seppili,op. cit.pp. 404-5; H. Maudsley: Physiology of Mind (1876), pp. 138 ff., 197 ff., and 241 ff. In G. H. Lewes's Physical Basis of Mind, Problem IV: 'The Reflex Theory,' a very full history of the question is given.
[69]Cf. Ferrier's Functions, pp. 120, 147, 414. See also Vulpian: Leçons sur la Physiol. du Syst. Nerveux, p. 548; Luciani u. Seppili,op. cit.pp. 404-5; H. Maudsley: Physiology of Mind (1876), pp. 138 ff., 197 ff., and 241 ff. In G. H. Lewes's Physical Basis of Mind, Problem IV: 'The Reflex Theory,' a very full history of the question is given.
[70]Goltz: Pflüger's Archiv, vol. 8, p. 460; Freusberg:ibid.vol. 10, p. 174.
[70]Goltz: Pflüger's Archiv, vol. 8, p. 460; Freusberg:ibid.vol. 10, p. 174.
[71]Goltz: Verrichtungen des Grosshirns, p. 78.
[71]Goltz: Verrichtungen des Grosshirns, p. 78.
[72]Loeb: Pflüger's Archiv, vol. 89, p. 276.
[72]Loeb: Pflüger's Archiv, vol. 89, p. 276.
[73]Ibid.p. 289.
[73]Ibid.p. 289.
[74]Schrader:ibid.vol. 44, p. 218.
[74]Schrader:ibid.vol. 44, p. 218.
[75]The Nervous System and the Mind (1888), chaps. iii, vi; also in Brain, vol. xi, p. 361.
[75]The Nervous System and the Mind (1888), chaps. iii, vi; also in Brain, vol. xi, p. 361.
[76]Brown-Séquard has given a resume of his opinions in the Archives de Physiologie for Oct. 1889, 5me. Série, vol. i, p 751.
[76]Brown-Séquard has given a resume of his opinions in the Archives de Physiologie for Oct. 1889, 5me. Série, vol. i, p 751.
[77]Goltz first applied the inhibition theory to the brain in his 'Verrichtungen des Grosshirns,' p. 39 ff. On the general philosophy of Inhibition the reader may consult Brunton's 'Pharmakology and Therapeutics,' p. 154 ff., and also 'Nature,' vol. 27, p. 419 ff.
[77]Goltz first applied the inhibition theory to the brain in his 'Verrichtungen des Grosshirns,' p. 39 ff. On the general philosophy of Inhibition the reader may consult Brunton's 'Pharmakology and Therapeutics,' p. 154 ff., and also 'Nature,' vol. 27, p. 419 ff.
[78]E.g. Herzen, Herman u. Schwalbe's Jahres-bericht for 1886, Physiol. Abth. p. 38. (Experiments on new-born puppies.)
[78]E.g. Herzen, Herman u. Schwalbe's Jahres-bericht for 1886, Physiol. Abth. p. 38. (Experiments on new-born puppies.)
[79]François-Franck:op. cit.p. 382. Results are somewhat contradictory.
[79]François-Franck:op. cit.p. 382. Results are somewhat contradictory.
[80]Pflüger's Archiv, vol. 42, p. 419.
[80]Pflüger's Archiv, vol. 42, p. 419.
[81]Neurologisches Centralblatt, 1889, p. 372.
[81]Neurologisches Centralblatt, 1889, p. 372.
[82]Op. cit.p. 387. See pp. 378 to 388 for a discussion of the whole question. Compare also Wundt's Physiol. Psych., 3d ed., i, 225 ff., and Luciani u. Seppili, pp. 243, 293.
[82]Op. cit.p. 387. See pp. 378 to 388 for a discussion of the whole question. Compare also Wundt's Physiol. Psych., 3d ed., i, 225 ff., and Luciani u. Seppili, pp. 243, 293.
[83]The Chapters on Habit, Association, Memory, and Perception will change our present preliminary conjecture that that is one of its essential uses, into an unshakable conviction.
[83]The Chapters on Habit, Association, Memory, and Perception will change our present preliminary conjecture that that is one of its essential uses, into an unshakable conviction.
[84]Pflüger's Archiv, vol. 41, p. 75 (1887).
[84]Pflüger's Archiv, vol. 41, p. 75 (1887).
[85]Ibid.vol. 44, p. 175 (1889).
[85]Ibid.vol. 44, p. 175 (1889).
[86]Untersuchungen über die Physiologie des Froschhirns. 1885.
[86]Untersuchungen über die Physiologie des Froschhirns. 1885.
[87]Loc. cit.pp. 80, 82-3. Schrader also found abiting-reflexdeveloped when the medulla oblongata is cut through just behind the cerebellum.
[87]Loc. cit.pp. 80, 82-3. Schrader also found abiting-reflexdeveloped when the medulla oblongata is cut through just behind the cerebellum.
[88]Berlin Akad. Sitzungsberichte for 1886.
[88]Berlin Akad. Sitzungsberichte for 1886.
[89]Comptes Rendus, vol. 102, p. 90.
[89]Comptes Rendus, vol. 102, p. 90.
[90]Comptes Rendus de l'Acad. d. Sciences, vol. 102, p. 1530.
[90]Comptes Rendus de l'Acad. d. Sciences, vol. 102, p. 1530.
[91]Loc. cit.p. 210.
[91]Loc. cit.p. 210.
[92]Goltz: Pflüger's Archiv, vol. 42, p. 447; Schrader:ibid.vol. 44, p. 219 ff. It is possible that this symptom may be an effect of traumatic inhibition, however.
[92]Goltz: Pflüger's Archiv, vol. 42, p. 447; Schrader:ibid.vol. 44, p. 219 ff. It is possible that this symptom may be an effect of traumatic inhibition, however.
[93]A few years ago one of the strongest arguments for the theory that the hemispheres are purely supernumerary was Soltmann's often-quoted observation that in new-born puppies the motor zone of the cortex is not excitable by electricity and only becomes so in the course of a fortnight, presumably after the experiences of the lower centres have educated it to motor duties. Paneth's later observations, however, seem to show that Soltmann may have been misled through overnarcotizing his victims (Pflüger's Archiv, vol. 37, p. 202). In the Neurologisches Centralblatt for 1889, p. 513, Bechterew returns to the subject on Soltmann's side without, however, noticing Paneth's work.
[93]A few years ago one of the strongest arguments for the theory that the hemispheres are purely supernumerary was Soltmann's often-quoted observation that in new-born puppies the motor zone of the cortex is not excitable by electricity and only becomes so in the course of a fortnight, presumably after the experiences of the lower centres have educated it to motor duties. Paneth's later observations, however, seem to show that Soltmann may have been misled through overnarcotizing his victims (Pflüger's Archiv, vol. 37, p. 202). In the Neurologisches Centralblatt for 1889, p. 513, Bechterew returns to the subject on Soltmann's side without, however, noticing Paneth's work.
[94]Münsterberg (Die Willenshandlung, 1888, p. 134) challenges Meynert's schemein toto, saying that whilst we have in our personal experience plenty of examples of acts which were at first voluntary becoming secondarily automatic and reflex, we have no conscious record of a single originally reflex act growing voluntary.—As far as conscious record is concerned, we could not possibly have it even if the Meynert scheme were wholly true, for the education of the hemispheres which that scheme postulates must in the nature of things antedate recollection. But it seems to me that Münsterberg's rejection of the scheme may possibly be correct as regards reflexes from thelower centres. Everywhere in this department of psychogenesis we are made to feel how ignorant we really are.
[94]Münsterberg (Die Willenshandlung, 1888, p. 134) challenges Meynert's schemein toto, saying that whilst we have in our personal experience plenty of examples of acts which were at first voluntary becoming secondarily automatic and reflex, we have no conscious record of a single originally reflex act growing voluntary.—As far as conscious record is concerned, we could not possibly have it even if the Meynert scheme were wholly true, for the education of the hemispheres which that scheme postulates must in the nature of things antedate recollection. But it seems to me that Münsterberg's rejection of the scheme may possibly be correct as regards reflexes from thelower centres. Everywhere in this department of psychogenesis we are made to feel how ignorant we really are.
[95]Pflüger's Archiv, vol. 44, p. 230-1.
[95]Pflüger's Archiv, vol. 44, p. 230-1.
[96]Naturally, as Schiff long ago pointed out (Lehrb. d. Muskel-u. Nervenphysiologie, 1859, p. 213 ff.), the 'Rückenmarksseele,' if it now exist, can have no higher sense-consciousness, for its incoming currents are solely from the skin. But it may, in its dim way, both feel, prefer, and desire. See, for the view favorable to the text: G. H. Lewes, The Physiology of Common Life (1860), chap. ix. Goltz (Nervencentren des Frosches 1869, pp. 102-130) thinks that the frog's cord has no adaptative power. This may be the case in such experiments as his, because the beheaded frog's short span of life does not give it time to learn the new tricks asked for. But Rosenthal (Biologisches Centralblatt, vol. iv, p. 247) and Mendelssohn (Berlin Akad. Sitzungsberichte, 1885, p. 107) in their investigations on the simple reflexes of the frog's cord, show that there is some adaptation to new conditions, inasmuch as when usual paths of conduction are interrupted by a cut, new paths are taken. According to Rosenthal, these grow more pervious (i.e. require a smaller stimulus) in proportion as they are more often traversed.
[96]Naturally, as Schiff long ago pointed out (Lehrb. d. Muskel-u. Nervenphysiologie, 1859, p. 213 ff.), the 'Rückenmarksseele,' if it now exist, can have no higher sense-consciousness, for its incoming currents are solely from the skin. But it may, in its dim way, both feel, prefer, and desire. See, for the view favorable to the text: G. H. Lewes, The Physiology of Common Life (1860), chap. ix. Goltz (Nervencentren des Frosches 1869, pp. 102-130) thinks that the frog's cord has no adaptative power. This may be the case in such experiments as his, because the beheaded frog's short span of life does not give it time to learn the new tricks asked for. But Rosenthal (Biologisches Centralblatt, vol. iv, p. 247) and Mendelssohn (Berlin Akad. Sitzungsberichte, 1885, p. 107) in their investigations on the simple reflexes of the frog's cord, show that there is some adaptation to new conditions, inasmuch as when usual paths of conduction are interrupted by a cut, new paths are taken. According to Rosenthal, these grow more pervious (i.e. require a smaller stimulus) in proportion as they are more often traversed.
[97]Whether this evolution takes place through the inheritance of habits acquired, or through the preservation of lucky variations, is an alternative which we need not discuss here. We shall consider it in the last chapter in the book. For our present purpose themodus operandiof the evolution makes no difference, provided it be admitted to occur.
[97]Whether this evolution takes place through the inheritance of habits acquired, or through the preservation of lucky variations, is an alternative which we need not discuss here. We shall consider it in the last chapter in the book. For our present purpose themodus operandiof the evolution makes no difference, provided it be admitted to occur.
[98]See Schrader's Observations,loc. cit.
[98]See Schrader's Observations,loc. cit.
The elementary properties of nerve-tissue on which the brain-functions depend are far from being satisfactorily made out. The scheme that suggests itself in the first instance to the mind, because it is so obvious, is certainly false: I mean the notion that each cell stands for an idea or part of an idea, and that the ideas are associated or 'bound into bundles' (to use a phrase of Locke's) by the fibres. If we make a symbolic diagram on a blackboard, of the laws of association between ideas, we are inevitably led to draw circles, or closed figures of some kind, and to connect them by lines. When we hear that the nerve-centres contain cells which send off fibres, we say that Nature has realized our diagram for us, and that the mechanical substratum of thought is plain. Insomeway, it is true, our diagram must be realized in the brain; but surely in no such visible and palpable way as we at first suppose.[99]An enormous number of the cellular bodies in the hemispheres are fibreless. Where fibres are sent off they soon divide into untraceable ramifications; and nowhere do we see a simple coarse anatomical connection, like a line on the blackboard, between two cells. Too much anatomy has been found to order for theoretic purposes, even by the anatomists; and the popular-science notions of cells and fibres are almost wholly wide of the truth. Let us therefore relegate the subject of theintimateworkings of the brain tothe physiology of the future, save in respect to a few points of which a word must now be said. And first of
in the same nerve-tract. This is a property extremely important for the understanding of a great many phenomena of the neural, and consequently of the mental, life; and it behooves us to gain a clear conception of what it means before we proceed any farther.
The law is this, thata stimulus which would be inadequate by itself to excite a nerve-centre to effective discharge may, by acting with one or more other stimuli (equally ineffectual by themselves alone) bring the discharge about. The natural way to consider this is as a summation of tensions which at last overcome a resistance. The first of them produce a 'latent excitement' or a 'heightened irritability'—the phrase is immaterial so far as practical consequences go; the last is the straw which breaks the camel's back. Where the neural process is one that has consciousness for its accompaniment, the final explosion would in all cases seem to involve a vivid state of feeling of a more or less substantive kind. But there is no ground for supposing that the tensions whilst yet submaximal or outwardly ineffective, may not also have a share in determining the total consciousness present in the individual at the time. In later chapters we shall see abundant reason to suppose that they do have such a share, and that without their contribution the fringe of relations which is at every moment a vital ingredient of the mind's object, would not come to consciousness at all.
The subject belongs too much to physiology for the evidence to be cited in detail in these pages. I will throw into a note a few references for such readers as may be interested in following it out,[100]and simply say that the directelectrical irritation of the cortical centres sufficiently proves the point. For it was found by the earliest experimenters here that whereas it takes an exceedingly strong current to produce any movement when a single induction-shock is used, a rapid succession of induction-shocks ('faradization') will produce movements when the current is comparatively weak. A single quotation from an excellent investigation will exhibit this law under further aspects:
"If we continue to stimulate the cortex at short intervals with the strength of current which produces the minimal muscular contraction [of the dog's digital extensor muscle], the amount of contraction gradually increases till it reaches the maximum. Each earlier stimulation leaves thus an effect behind it, which increases the efficacy of the following one. In this summation of the stimuli.... the following points may be noted: 1) Single stimuli entirely inefficacious when alone may become efficacious by sufficiently rapid reiteration. If the current used is very much less than that which provokes the first beginning of contraction, a very large number of successive shocks may be needed before the movement appears—20, 50, once 106 shocks were needed. 2) The summation takes place easily in proportion to the shortness of the interval between the stimuli. A current too weak to give effective summation when its shocks are 3 seconds apart will be capable of so doing when the interval is shortened to 1 second. 3) Not only electrical irritation leaves a modification which goes to swell the following stimulus, but every sort of irritant which can produce a contraction does so. If in any way a reflex contraction of the muscle experimented on has been produced, or if it is contracted spontaneously by the animal (as not unfrequently happens 'by sympathy,' during a deep inspiration), it is found that an electrical stimulus, until then inoperative, operates energetically if immediately applied."[101]
"If we continue to stimulate the cortex at short intervals with the strength of current which produces the minimal muscular contraction [of the dog's digital extensor muscle], the amount of contraction gradually increases till it reaches the maximum. Each earlier stimulation leaves thus an effect behind it, which increases the efficacy of the following one. In this summation of the stimuli.... the following points may be noted: 1) Single stimuli entirely inefficacious when alone may become efficacious by sufficiently rapid reiteration. If the current used is very much less than that which provokes the first beginning of contraction, a very large number of successive shocks may be needed before the movement appears—20, 50, once 106 shocks were needed. 2) The summation takes place easily in proportion to the shortness of the interval between the stimuli. A current too weak to give effective summation when its shocks are 3 seconds apart will be capable of so doing when the interval is shortened to 1 second. 3) Not only electrical irritation leaves a modification which goes to swell the following stimulus, but every sort of irritant which can produce a contraction does so. If in any way a reflex contraction of the muscle experimented on has been produced, or if it is contracted spontaneously by the animal (as not unfrequently happens 'by sympathy,' during a deep inspiration), it is found that an electrical stimulus, until then inoperative, operates energetically if immediately applied."[101]
Furthermore:
"In a certain stage of the morphia-narcosis an ineffectively weak shock will become powerfully effective, if, immediately before its applicationto the motor centre, the skin of certain parts of the body is exposed to gentle tactile stimulation.... If, having ascertained the subminimal strength of current and convinced one's self repeatedly of its inefficacy, we draw our hand a single time lightly over the skin of the paw whose cortical centre is the object of stimulation, we find the current at once strongly effective. The increase of irritability lasts some seconds before it disappears. Sometimes the effect of a single light stroking of the paw is only sufficient to make the previously ineffectual current produce a very weak contraction. Repeating the tactile stimulation will then, as a rule, increase the contraction's extent."[102]
"In a certain stage of the morphia-narcosis an ineffectively weak shock will become powerfully effective, if, immediately before its applicationto the motor centre, the skin of certain parts of the body is exposed to gentle tactile stimulation.... If, having ascertained the subminimal strength of current and convinced one's self repeatedly of its inefficacy, we draw our hand a single time lightly over the skin of the paw whose cortical centre is the object of stimulation, we find the current at once strongly effective. The increase of irritability lasts some seconds before it disappears. Sometimes the effect of a single light stroking of the paw is only sufficient to make the previously ineffectual current produce a very weak contraction. Repeating the tactile stimulation will then, as a rule, increase the contraction's extent."[102]
We constantly use the summation of stimuli in our practical appeals. If a car-horse balks, the final way of starting him is by applying a number of customary incitements at once. If the driver uses reins and voice, if one bystander pulls at his head, another lashes his hind quarters, and the conductor rings the bell, and the dismounted passengers shove the car, all at the same moment, his obstinacy generally yields, and he goes on his way rejoicing. If we are striving to remember a lost name or fact, we think of as many 'cues' as possible, so that by their joint action they may recall what no one of them can recall alone. The sight of a dead prey will often not stimulate a beast to pursuit, but if the sight of movement be added to that of form, pursuit occurs. "Brücke noted that his brainless hen, which made no attempt to peck at the grain under her very eyes, began pecking if the grain were thrown on the ground with force, so as to produce a rattling sound."[103]"Dr. Allen Thomson hatched out some chickens on a carpet, where he kept them for several days. They showed no inclination to scrape,... but when Dr. Thomson sprinkled a little gravel on the carpet,... the chickens immediately began their scraping movements."[104]A strange person, and darkness, are both of them stimuli to fear and mistrust in dogs (and for the matter of that, in men). Neither circumstancealone may awaken outward manifestations, but together, i.e. when the strange man is met in the dark, the dog will be excited to violent defiance.[105]Street-hawkers well know the efficacy of summation, for they arrange themselves in a line upon the sidewalk, and the passer often buys from the last one of them, through the effect of the reiterated solicitation, what he refused to buy from the first in the row. Aphasia shows many examples of summation. A patient who cannot name an object simply shown him, will name it if he touches as well as sees it, etc.
Instances of summation might be multiplied indefinitely, but it is hardly worth while to forestall subsequent chapters. Those on Instinct, the Stream of Thought, Attention, Discrimination, Association, Memory, Æsthetics, and Will, will contain numerous exemplifications of the reach of the principle in the purely psychological field.
One of the lines of experimental investigation most diligently followed of late years is that of the ascertainment of thetime occupied by nervous events. Helmholtz led off by discovering the rapidity of the current in the sciatic nerve of the frog. But the methods he used were soon applied to the sensory nerves and the centres, and the results caused much popular scientific admiration when described as measurements of the 'velocity of thought.' The phrase 'quick as thought' had from time immemorial signified all that was wonderful and elusive of determination in the line of speed; and the way in which Science laid her doomful hand upon this mystery reminded people of the day when Franklin first 'eripuit cœlo fulmen,' foreshadowingthe reign of a newer and colder race of gods. We shall take up the various operations measured, each in the chapter to which it more naturally pertains. I may say, however, immediately, that the phrase 'velocity ofthought' is misleading, for it is by no means clear in any of the cases what particular act of thought occurs during the time which is measured. 'Velocity of nerve-action' is liable to the same criticism, for in most cases we do not know what particular nerve-processes occur. What the times in question really represent is the total duration of certainreactions upon stimuli. Certain of the conditions of the reaction are prepared beforehand; they consist in the assumption of those motor and sensory tensions which we name the expectant state. Just what happens during the actual time occupied by the reaction (in other words, just what is added to the pre-existent tensions to produce the actual discharge) is not made out at present, either from the neural or from the mental point of view.
The method is essentially the same in all these investigations. A signal of some sort is communicated to the subject, and at the same instant records itself on a time-registering apparatus. The subject then makes a muscular movement of some sort, which is the 'reaction,' and which also records itself automatically. The time found to have elapsed between the two records is the total time of that observation. The time-registering instruments are of various types. One type is that of the revolving drum covered with smoked paper, on which one electric pen traces a line which the signal breaks and the 'reaction' draws again; whilst another electric pen (connected with a pendulum or a rod of metal vibrating at a known rate) traces alongside of the formerline a 'time-line' of which each undulation or link stands for a certain fraction of a second, and against which the break in the reaction-line can be measured. Compare Fig. 21, where the line is broken by the signal at the first arrow, and continued again by the reaction at the second. Ludwig's Kymograph, Marey's Chronograph are good examples of this type of instrument.