752 OF THE FUNCTIONS OF THE NERVOUS SYSTEM. 



virtue of their intellectual achievements, may be stated as a proposition of 

 equal generality. In these opposite cases, we witness most distinctly the anta- 

 gonism between the Instinctive and Voluntary powers. Those unfortunate 

 beings, in whom the Cerebrum is but little developed, are guided almost solely 

 by their instinctive tendencies ; which frequently manifest themselves with a 

 degree of strength that would not have been supposed to exist : and occasionally 

 new instincts present themselves, of which the Human being is ordinarily re- 

 garded as destitute. 1 On the other hand, those who have obtained most in- 

 fluence over the understandings of others have always been large-brained per- 

 sons, of strong intellectual and volitional powers, whose emotional tendencies 

 have been subordinated to the reason and will, and who have devoted their 

 whole energy to the particular objects of their pursuit. It is very different, 

 however, with those who are actuated by what is ordinarily termed genius ; and 

 whose influence is rather upon the feelings and intuitions, than upon the under- 

 standings of others. Such persons are often very deficient in the power of even 

 comprehending the ordinary affairs of life ; and still more commonly, they show 

 an extreme want of judgment in the management of them, being under the im- 

 mediate influence of their passions and emotions, which they do not sufficiently 

 endeavor to control by their intelligent will. The life of a " genius," whether 

 his bent be towards poetry, music, painting, or pursuits of a more material cha- 

 racter, is seldom one which can be held up for imitation. In such persons, the 

 general power of the mind being low, the Cerebrum is not usually found of any 

 great size. The mere comparative size of the Cerebrum, however, affords no ac- 

 curate measure of the amount of mental power : we not unfrequently meet with 

 men possessing large and well-formed heads ; whilst their physical capability is 

 not greater than that of others, the dimensions of whose crania have the same 

 general proportion, but are of much less absolute size. Large brains, with de- 

 ficient activity, are commonly found in persons of what has been termed the 

 phlegmatic temperament, in whom the general processes of life seem in a torpid 

 and indolent state; whilst small brains and great activity betoken what are 

 known as the sanguine and nervous temperaments. 



784. Having now inquired into the evidence of the general functions of the 

 Cerebrum, which may be derived from examination of its Comparative develop- 

 ment, we proceed to our other sources of information, Experiment and Patho- 

 logical phenomena. From neither of these, however, is much positive informa- 

 tion to be derived. The results of partial mutilations are usually, in the first 

 instance, a general disturbance of the Cerebral functions ; which subsequently, 

 however, more or less subsides, leaving but little apparent affection of the ani- 

 mal functions, except muscular weakness. The whole of one Hemisphere has 

 been removed in this way without any evident consequence, save a temporary 

 feebleness of the limbs on the opposite side of the body, and what was supposed 

 to be a deficiency of sight through the opposite eye. The former was speedily 

 recovered from, and the animal performed all its movements as well as before ; 

 the latter, however, was permanent, but the pupil remained active. When the 

 upper part, only, of both Cerebral Hemispheres was removed by Hertwig, the 

 animal was reduced, for fifteen days, to nearly the same condition with the one 

 from which they had been altogether withdrawn ; but, afterwards, sensibility 

 evidently returned, and the muscular power did not appear to be much dimi- 

 nished. The effects of the entire removal of the Cerebral Hemispheres have 

 been already stated ( 734). So far as any inferences can be safely drawn from 



1 A remarkable instance of this was published some years since. A perfectly idiotic 

 girl, in Paris, having been seduced by some miscreant, was delivered of a child without 

 assistance ; and it was found that she had gnawed the umbilical cord in two, in the same 

 manner as is practised by the lower animals. It is scarcely to be supposed that she had 

 any idea of the object of this separation. 



