Page:Principles of Psychology (1890) v1.djvu/90

70 70 PSTCHOLOGT. cortex surrounding the wound without exciting the limb to movement, and ablate it, without bringing back the vanished palsy.* It would accordingly seem that the cere- bral centres below the cortex must be the seat of the regained activities. But Goltz destroyed a dog's entire left hemi- sphere, together with the corpus striatum and the thalamus on that side, and kept him alive until a surprisingly small amount of motor and tactile disturbance remained.t These centres cannot here have accounted for the restitution. He has even, as it would appear,| ablated both the hemispheres of a dog, and kept him alive 61 days, able to walk and stand. The corpora striata and thalami in this dog were also prac- tically gone. In view of such results we seem driven, with M. rran§ois-Franck,§ to fall back on the ganglia lower stilly or even on the spinal cord as the ' vicarious ' organ of which we are in quest. If the abeyance of function between the operation and the restoration was due exclusively to inhibi- tion, then we must suppose these lowest centres to be in reality extremely accomplished organs. They must always have done what we now find them doing after function is restored, even when the hemispheres were intact. Of course this is conceivably the case ; yet it does not seem very plausible. And the a priori considerations which a moment since I said I should urge, make it less plausible still. For, in the first place, the brain is essentially a place of currents, which run in organized paths. Loss of function can only mean one of two things, either that a current can no longer run in, or that if it runs in, it can no longer run out, by its old path. Either of these inabilities may come from a local ablation; and * restitution ' can then only mean that, in spite of a temporary block, an inrunning current has at last become enabled to flow out by its old path again — e.g., the sound of 'give your paw' discharges after some f Pflilger's Archiv, vol. 43, p. 419. X Neurologisches Centralblatt, 1889, p. 373. § 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. 335 ff., and Luciani u. Seppili, pp. 343, 293.
 * Fran9ois-Franck : op. cit. p. 383. Results are somewhat contradictory.