Page:Principles of Psychology (1890) v1.djvu/88

68 68 PSYCHOLOGY. tion, for control of the spliincters, etc., which could be excited to activity by tactile stimuli and as readily reinhib- ited by others simultaneously applied.* We may therefore plausibly suppose that the rapid reappearance of motility, vision, etc., after their first disappearance in consequence of a cortical mutilation, is due to the passing off of inhibitions exerted by the irritated surface of the wound. The only question is whether all restorations of function must be explained in this one simple way, or whether some part of them may not be owing to the formation of entirely new paths in the remaining centres, by which they become In favor of an indefinite extension of the inhibition theory facts may be cited such as the following : In dogs whose dis- turbances due to cortical lesion have disappeared, they may in consequence of some inner or outer accident reappear in all their intensity for 24 hours or so and then disappear again, f In a dog made half blind by an operation, and then shut up in the dark, vision comes back just as quickly as in other similar dogs whose sight is exercised systematically every day.:}: A dog which has learned to beg before the operation recommences this practice quite spontaneously a week after a double-sided ablation of the motor zone.§ Occasionally, in a pigeon (or even, it is said, in a dog) we see the disturbances less marked immediately after the operation than they are half an hour later. I This would be impossible were they due to the subtraction of the organs which normally carried them on. Moreover the entire drift of recent physiological and pathological specu- lation is towards enthroning inhibition as an ever-present and indispensable condition of orderly activity. We shall see how great is its importance, in the chapter on the Will. Mr. Charles Mercier considers that no muscular contraction, once begun, would ever stop without it, short of exhaustion f Goltz : Verrichtungen des Grosshirns. p. 73. X Loeb : Pfltlger's Archiv, vol. 39, p. 276. § Ibid. p. 289. II Schrader : ibid. vol. 44, p. 218.
 * educated ' to duties which they did not originally possess.
 * Goltz : Pfliiger's Archiv, vol. 8, p. 460; Freusberg: ibul. vol. 10, p. 174.