THE CEREBRUM 133 



to show any token of consciousness. The postmortem 

 examination showed entire lack of the cerebral hemi- 

 .spheres. 



When we compare this shocking instance with the case 

 of the dog or the pigeon, we are led to believe that the 

 human cerebrum is of such overwhelming dominance that 

 many functions which in the lower animals can be sub- 

 served by other parts of the brain have been largely trans- 

 ferred to it. In man it is probable that the subordinate 

 centers for the eyes are incapable of any extensive or 

 useful reaction when their cerebral connections are severed. 

 It is not likely that the power to balance and to walk 

 could be preserved in man as in the dog through the 

 agency of the midbrain, cerebellum, and medulla without 

 the cerebrum. To be sure, the decerebrate child had 

 never learned to walk, and it might be urged that the 

 cerebrum might be essential for the attentive act of learn- 

 ing and not for exercising the power when acquired. But 

 we have many other cases in which the ability to walk 

 was lost when only a limited part of the cerebrum had 

 suffered injury. 



In apes, which approach the human type of organization, 

 the loss of a restricted region from the cerebrum is said to 

 lead to absolute blindness so far as can be determined. 

 The power to avoid obstacles, so striking in the dog and 

 the pigeon, entirely disappears. In all probability, a 

 decerebrate human being would be deaf, despite the fact 

 that the auditory nerve would retain its connection with 

 the medulla and so with the remainder of the nervous 

 system. Pigeons without the cerebrum respond to cer- 

 tain sounds by sluggish movements. 



Granting, as we must, that the cerebrum is essential to 

 intelligence and to all action based upon individual ex- 

 perience, we are at once led to inquire whether it is all 

 alike or whether particular parts have particular func- 

 tions. In other words, is there cerebral localization of a 

 definite character? This question was asked by Flourens 

 long ago, and he attempted to answer it on the basis of 



