Page:Principles of Psychology (1890) v1.djvu/89

69 FUNCTIONS OF THE BBAIN. 69 of the system ; * and Brown-Sequard has for years been accumulating examples to show how far its influence ex- tends, f Under these circumstances it seems as if error might more probably lie in curtailing its sphere too much than in stretching it too far as an explanation of the phenomena following cortical lesion. :|: On the other hand, if we admit no re-education of cen- tres, we not only fly in the face of an a priori probability, but we find ourselves compelled by facts to sujDpose an almost incredible number of functions natively lodged in the centres below the thalami or even in those below the corpora quadrigemina. I will consider the a priori objection after first taking a look at the facts which I have in mind. They confront us the moment we ask ourselves just which are the parts ivhich perform the functions abolished by an operation after sufficient time has elapsed for restoration to occur ? The first observers thought that they must be the cor- responding parts of the opposite or intact hemisphere. But as long ago as 1875 Carville and Duret tested this by cutting out the fore-leg-centre on one side, in a dog, and then, after waiting till restitution had occurred, cutting it out on the opposite side as well. Goltz and others have done the same thing. § If the opposite side were really the seat of the restored function, the original palsy should have appeared again and been permanent. But it did not appear at all ; there appeared only a palsy of the hitherto unaffected side. The next supposition is that the parts surrounding the cut-out region learn vicariously to perform its duties. But here, again, experiment seems to upset the hypothesis, so far as the motor zone goes at least ; for we may wait till motility has returned in the affected limb, and then both irritate the Brain, vol. xi. p. 361. f Brown-Sequard has given a resume of his opinions in the Archives de Physiologie for Oct. 1889, 5me. Serie, vol. i, p 751. X Goltz first applied the inhibition theory to the brain in his ' Verrich- tungen 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. § E.g. Herzen, Herman u. Schwalbe's Jahres-bericht for 1886, Physiol. Abth. p. 38. (Experiments on new-born puppies.)
 * The Nervous System and the Mind (1888), chaps, iii, vi; also in