FUNCTIONS OF THE CEREBRAL HEMISPHERES. 107 



facts have led physiologists mostly to adopt the opinion that the ce- 

 rebellum has for its function, the regulation and karmonisation, or 

 co-ordinatio7i of muscular movements, especially those of a volun- 

 tary character. 



This opinion is further substantiated by the observations of Leiiret 

 and Lassaigne, which show conclusively that the cerebellum is larger 

 in geldings, which are commonly used for draught purposes, and in 

 whom the number of muscles employed is consequently great, than 

 it is either in the mare or stallion, the latter of which is kept espe- 

 cially for the purpose of propagation, and is much less applied to 

 occupations which call forth their motor faculties. The cerebellum 

 is connected with the medulla oblongata and spinal cord by the festi- 

 form bodies, and the posterior columns of the cord, and with the 

 mesocephale by the fibres of the pons. Thus this organ is brought 

 into union with each segment of the great nervous centre, upon 

 which all the movements and sensation of the body depend. 



FUNCTIONS OF THE CEREBRAL HEMISPHERES. 



The fact of the cerebral hemispheres having a more perfect deve- 

 lopment in proportion as the animals in which we examine them 

 are higher in the scale of vertebrata, from fishes up to man, and the 

 coincidence of atrophy, and the absence of the convolutions on their 

 surface with idiocy, are alone sufficient to indicate that the seat of 

 the higher intellectual faculties must be sought for in this part of the 

 encephalon. The primitive fibres which go to the constitution of the 

 cerebral hemispheres have least of all to do with the simple motory 

 and sensitive operations of the nervous substance. All inquirers 

 agree in representing the hemispheres as altogether insensible; they 

 may be cut, pricked, and either partially or entirely removed without 

 any feeling of pain being excited. Wounds of this part of the en- 

 cephalon, moreover, give rise to no convulsions ; the only constant 

 effect of a deep incision is blindness of the eye of the opposite side, 

 and a state of stupidity. These investigations, while they render 

 more precise the functions of the cerebrum, have also tended to limit 

 them. 



It has also been shown that this organ is not essential to life, that 

 it must be considered as an organ superadded for particular pur- 

 poses ; that it has no representative in the lowest classes of animals, 

 and that when it first makes its appearance in fishes it evidently per- 

 forms a subordinate part in the general actions of the nervous sys- 

 tem. Hence, whatever be its function, it should be remembered that 

 it does not deprive other parts of their independent powers, although 

 it may keep them in check, and considerably modify their manifes- 

 tation. 



The experiments instituted by the same physiologists above men- 

 tioned, go to prove that the cerebrum is the organ of intelligence. 



