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221 Descartes compares the animal mechanism to that of the grottos and fountains at Versailles, the nerves to the water-tubes:—“Les objets extérieurs qui par leur seul présence, agissent contre les organes des sens, et qui par ce moyen, la déterminent à se mouvoir en plusieurs diverses façons, selon comme les parties du cerveau sont disposées, sont comme les étrangers, qui entrant dans quelques unes des grottes de ces fontaines causent euxmêmes sans y penser les mouvements qui s’y font en leur présence: car ils n’y peuvent entrer qu’en marchant sur certains carreaux tellement disposés, que s’ils approchent d’une Diane qui se baigne, ils la font cacher dans les roseaux; et s’ils passent outre pour la poursuivre, ils feront venir vers eux un Neptune qui les menacera de son trident; ou s’ils vont de quelque autre costé, ils en feront sortir un monstre marin qui leur vomira de l’eau contre la face.”—Traité de l’Homme, 1664, p. 12. Ingenious as the comparison is, it only illustrates how machines may be constructed to imitate animal actions. Diana always hides herself when a certain spot is trodden upon; and Neptune always appears when another spot is trodden upon. There is no fluctuation, no sensibility discerning differences and determining variations. Compare the following experiment: A monkey was placed on the table and a shrill whistle made close to its ear: “Immediately the ear was pricked and the animal turned with an air of intense surprise, with eyes widely opened and pupils dilated, to the direction whence the sound proceeded. On repetition of the experiment several times, though the pricking of the ear and the turning of the head and eyes constantly occurred, the look of surprise and dilatation of the pupils ceased to be manifested.”—Ferrier, The Functions of the Brain, 1876, p. 171. A mechanical monkey would always have reacted in precisely the same way on each stimulus.
222 Printed in the Fortnightly Review, November, 1874, from which all my citations are made.
223 Schiff, Lehrbuch der Physiol., 1858, p. 212. Hermann, Physiology, translated by Gamgee, 1875, p. 511.
224 Meanwhile the reader is referred to Schröder van der Kolk, Pathologie der Geisteskrankheiten, 1863, p. 51; or Jessen, Physiologie des menschlichen Denkens, 1872, p. 66.
225 Griesinger, Les Maladies Mentales, p. 96.
226 M. Luys cites the case of a patient who conversed quite rationally with a visitor “sans en avoir conscience, et ne se souvenait de rien”; and he draws the extraordinary conclusion that the conversation “s’opérait en vertu des forces réflexes.”—Études de Physiologie et de Pathologie Cérébrales, 1874, p. 117. Is it not obvious that the patient must have been conscious at the time, though the consciousness vanished like that in a dream? The persistent consciousness is the continuous linking on of one state with previous states—the apperception of the past.
227 Abercrombie, Inquiries concerning the Intellectual Powers, 1840, p. 151. Wigan, The Duality of the Mind, 1844, p. 270. Despine, La Psychologie Naturelle, 1868, I. 54.
228 Dr. Hughlings Jackson has quite recently cited some curious examples in his own practice. See West Riding Lunatic Asylum Reports for 1875.
229 Problems, Vol. II. p. 478, sq.
230 “Le sentiment fait naître le mouvement, et le mouvement donne naissance au sentiment.”—Van Deen, Traités et Découvertes sur la Moëlle Épinière, 1841, p. 102.
231 Dr. Carpenter tells a similar story of Admiral Codrington, who, when a midshipman, could always be awakened from the profoundest slumber if the word “signal” were uttered; whereas no other word disturbed him.
232 Compare an interesting personal example given by Jouffroy, quoted in Sir W. Hamilton’s Lectures, I. 331.
233 Lancet, 10th July, 1858.
234 Marshall Hall in Philos. Trans., 1833. Lectures on the Nervous System and its Diseases, 1836. New Memoir on the Nervous System, 1843.
235 MĂĽller, Physiology, I. 721.
236 It is better simply to remove the brain, than to remove the whole head, which causes a serious loss of blood. An etherized animal may be operated on with ease and accuracy. For many experiments, mere division of the spinal cord is better than decapitation. Great variations in the results must be expected, because the condition of the animal, its age and sex—whether fasting or digesting—whether the season be spring or summer—and a hundred other causes, complicate the experiment.
237 Volkmann, quoted by PflĂĽger.
238 Unzer, The Principles of Physiology (translated for the Sydenham Society), p. 235.
239 Even so eminent an investigator as Goltz has fallen into this confusion. He introduces an experiment to prove that the brainless frog is insensible to pain by the words “when an animal, placed under circumstances which would be very painful, makes no movement, although quite capable of moving, the least we can say is that it is improbable that the animal has sensation” (Nervencentren des Frosches, p. 127). I need not discuss the proof itself, having already done so in Nature, Vol. IX. p. 84. The point to which I wish to call attention is the confusion of insensibility in general with insensibility to pain.
240 See Duchenne, De Électrisation localisée, p. 398. Griesinger cites various examples of insane patients who have burned the flesh off their bones while manifesting a total indifference to these injuries. Maladies Mentales, p. 94. Falret says, “Nous avons vu plusieurs fois des aliénés s’inciser, s’amputer eux-mêmes diverses parties du corps sans paraître ressentir aucune souffrance.” Leçons cliniques de Médicine Mentale, 1854, I. 189. Patients incapable of feeling the contact of a hot iron with their skin have felt subjective burnings in the skin thus objectively insensible.
241 Cros, Les Fonctions supérieures du Syst. nerveux, 1875, p. 27.
242 Virchow’s Archiv, Bd. XXVIII. p. 30.
243 The idea of a fixed anatomical mechanism for reflexion, such as that of an excito-motory system, is completely refuted by the fact that the gray substance may anywhere be cut sway, and yet so long as a small bridge of gray substance remains the stimulation will be propagated through it. The idea of a fixed pathway is also refuted by the fact of the variations in the reflex responses, and the necessary irradiation even for very simple reflexes. Take, for example, that of breathing. An irritation of the bronchial filaments is transmitted by the pneumogastric to its centre in the medulla oblongata; from this, however, it is immediately irradiated downwards to the cervical and dorsal regions, which innervate the muscles of chest and diaphragm, and upwards to the brain, whether the stimulation awaken consciousness or not. One may say, indeed, that inasmuch as under normal conditions the bronchial irritation always causes a movement of a particular group of muscles, there is to this extent a fixed pathway of discharge; but, as I have formerly explained, this is only an expression of the particular tension of particular centres, and is variable with that tension; the other centres are also affected, even when they are not excited to discharge.
244 Lallemand, Recherches sur L’Encéphale, III. 310.
245 West Riding Lunatic Asylum Reports, 1875, Vol. V. pp. 252, sq.
246 Gall et Spurzheim, Anat. et Physiol. du Système Nerveux, I. 83.
247 Printed in the British and Foreign Medical Review, Jan. 1845.
248 Griesinger, Abhandlungen, 1872. The first volume contains a reprint of this memoir.
249 Landry, Traité des Paralysies, I. 55. Conf. Ziemssen, Chorea in the Handbuch der speciellen Pathologie, Bd. XII. 2, p. 408. And Luys, Études de physiol. et pathol. cérébrales, 1874, pp. 89–94.
250 Sue, Recherches Philosophiques sur la Vitalité et le Galvanisme, p. 9. He was not consistent, however, but adopted Bichat’s opinion respecting the sensibility of the viscera, p. 68.
251 Legallois, Expériences sur le principe de la vie. Published, I conclude, in 1811; the edition I use is the one printed in the Encyclopédie des Sciences Medicales, IV.
252 Wilson Philip, Experimental Inquiry into the Laws of the Vital Functions, pp. 209, 210.
253 Longet, Traité de Physiologie, II. 105.
254 He cites Cuvier, Majendie, Deamoulins, and Mayo as maintaining this error.
255 Grainger, Structure and Functions of the Spinal Cord, p. 66.
256 Nasse, Unters. zur Physiologie und Pathologie, Vol. II. Part 2.
257 Carus, System der Physiologie, III. 101.
258 J. W. Arnold, Die Lehre von der Reflex-Function, 86.
259 PflĂĽger, Die sensorischen Functionen des RĂĽckenmarks der Wirbelthiere.
260 Except Auerbach, who repeated and varied the experiments; and Funke, who partially adopted the conclusions in his systematic treatise on Physiology.
261 Schiff, Lehrbuch der Physiologie, 208.
262 Landry, Traité des Paralysies, 1859, maintains that the cord is a centre of sensation, and that there is in it a faculty analogous to the perception and judgment of the brain. Compare pp. 163 et sq. and 305. He also cites an essay by Dr. Paton of Edinburgh (Edinburgh Medical Journal, 1846), in which the sensational and volitional claims of the spinal cord are advanced.
263 Goltz, Beiträge zur Lehre von den Functionen der Nervencentren des Froeches, 1869.
264 Pflüger’s Archiv, Bd. XIV. p. 158.
265 See Prob. II. § 183.
266 “Il y a donc une mémoire par le cerveau et une mémoire par l’automate. Tous les organes ont une mémoire propre, c’est à dire une tendance à reproduire les séries d’actes qu’ils ont plusieurs fois executés.”—Gratiolet, Anat. du Système Nerveux, 1857, p. 464.
267 To obviate misunderstanding let me say that, unless the contrary is specified, I use the term Brain throughout this argument as equivalent to the cerebral hemispheres, because it is in these that sensation, volition, and consciousness are localized by the generality of writers, many of whom, indeed, regard the cells of the gray matter of the convolutions as the exclusive seat of these phenomena, dividing these cells into sensational, emotional, and intellectual. There are physiologists who extend sensation to the cerebral ganglia and gray masses of the medulla oblongata; but the medulla spinalis is so clearly continuous with the medulla oblongata that there is a glaring inconsistency in excluding sensation from the one if it is accorded to the other; and the grounds on which sensitive phenomena are admitted in the absence of the hemispheres, force us to admit analogous phenomena in the absence of the ganglia and medulla oblongata: in
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