FUNCTIONS OF THE FORE-BRAIN. 591 



exercised by the fore-brain on the lower centres is at least 

 as important as its power of exciting them; strength of 

 character depends, perhaps, more on great inhibitory power 

 in the fore-brain than on its initiating faculty. 



The intellectual powers seem mainly, if not entirely, de- 

 pendent for their necessary material antecedents or con- 

 comitants on the surface convolutions of the cerebral 

 hemispheres; if these alone be removed from an animal its 

 mental condition is much the same as if the whole fore- 

 brain be taken away. Some simple and fundamental 

 perceptions seem, however, to remain, having, perhaps, 

 their seats in the deeper gray masses constituting the 

 optic tlialami and corpora striata (p. 167); a dog, from 

 which the greater part of the cerebral surfaces had been re- 

 moved, after a time learnt to walk about, apparently volun- 

 tarily, and to find and eat his food; he even learned not to 

 take the food of other dogs after he had several times been 

 severely bitten for so doing. But more complex perceptions 

 were lost; before the operation, for example, he was violently 

 terrified by peeing a man fantastically dressed; but after- 

 wards no such things seemed to arouse in him so complex 

 a conception as that of a strange or dangerous object. 



Although the fore-brain is the seat of consciousness it is 

 itself insensible to cutting or wounding; and was long 

 supposed to be entirely inexcitable by general nerve stimuli. 

 It has, however, been found that tolerably powerful electri- 

 cal currents applied to the convolutions produce, in many 

 cases, definite movements; the nature of the movement 

 depending upon the area stimulated. Hence an attempt 

 nas been made to detect the functions of different parts of 

 the cerebral hemispheres by observing the results of stimu- 

 lating each; and provisionally we may, perhaps, assume that 

 the brain-centres, from which volitional impulses proceed to 

 the co-ordinating centres for the muscle-groups called into 

 play, lie in the cerebral regions whose stimulation is followed 

 by the movement. The animals, however, so often recover 

 the power of executing the movement spontaneously after 

 its supposed volitional centre has been removed that the 

 proper interpretation of the experimental results is still 



