364 INNERVATION. [CHAP. XI. 



Instances have been already referred to of animals of the same 

 group, although of different species, having brains very differently 

 developed as regards the convoluted surface. In the animal with 

 greater mental power, the convolutions are always deeper or more 

 complex (vid. p.. 283). 



If a similar comparison were instituted between the brains of 

 different men, whose intellectual powers had been known, there can 

 be no doubt that a similar result would be obtained. A series of 

 outline views of the convolutions of the brain in various known in- 

 dividuals would be of great interest and advantage in reference to 

 the question of their function. 



Thus anatomy leads to the conclusion that the operations of the 

 mind are associated with the convolutions. Perception, memory, 

 the power of abstraction, imagination, all possess, as instruments of 

 corporeal action, these folds of vesicular and fibrous matter. These 

 parts, in the language of Cuvier, are the sole receptacle in which the 

 various sensations may be as it were consummated, and become 

 perceptible to the animal. It is in these that all sensations take a 

 distinct form, and leave lasting traces of their impression ; they 

 serve as a seat to memory, a property by means of which the ani- 

 mal is furnished with materials for his judgments."* 



It is quite established as the result of all the experiments upon 

 the cerebral convolutions and the white matter of the centrum ovale, 

 that mechanical injury to them occasions no pain, nor disturbance of 

 motion. The endowments of the nerve-fibres which form the fibrous 

 substance of the cerebral convolutions appear to be quite distinct 

 from those of sensitive or motor nerves. They are internuncial 

 between parts which are beyond the immediate influence of the 

 ordinary physical agents, and which have no direct connexions with 

 muscular organs. And if, under the influence of morbid irritation, 

 they do excite pain or convulsion, which is frequently the case in 

 disease of the cerebral meninges, this is effected through a change 

 produced in the corpora striata or optic thalami propagated to the 

 origins of motor and sensitive nerves. 



The recorded experiments upon the removal of the hemispheres of 

 the brain do not lead to any satisfactory conclusion, as in all of them 

 the corpora striata and thalami have been removed at the same time. 

 But it may be here stated, that the effect of the removal of the hemi- 

 spheres in Flour ens' experiments was to throw the animal into a state 

 of deep sleep, retaining its full muscular power, yet apparently inca- 



* Cuvier, Eeport sur le M6moire de Flourens sur le SystSme nerveux. 



