CHAPTER XII. 



THE CEREBRAL HEMISPHERES. 



Pbysiological divisions of the encephalon Weight of different parts of the 

 brain and of the entire encephalon Some points in the physiological anat- 

 omy of the encephalon and its connections The cerebrum General prop- 

 erties of the cerebrum Functions of the cerebrum Extirpation of the 

 cerebrum in animals Pathological facts bearing upon the functions of 

 the cerebrum Comparative development of the cerebrum in the lower 

 animals Development of the cerebrum in different races of men and in 

 different individuals Ethnological table, derived from autopsies of white 

 and negro brains Table of weights of the encephalon in different indi- 

 viduals Location of the faculty of articulate language in a restricted por- 

 tion of the anterior cerebral lobes. 



THE anatomy of the encephalon is so complex, that it can 

 be treated of with advantage only by a very minute and care- 

 fully-illustrated description, such as is to be found in some 

 of the elaborate anatomical works or in special treatises on 

 the nervous system. We shall not consider under a distinct 

 head the general physiological anatomy of the brain, for the 

 reason just given, and also because we are as yet ignorant 

 of the exact connection between the structure and arrange- 

 ment of many of its parts and their physiology. "We know 

 that the gray substance is capable of appreciating general 

 and special impressions received by the peripheral nervous 

 system, and of generating the so-called nerve-force. Impres- 

 sions are conveyed to this portion of the cerebro-spinal axis 

 by the sensory conductors, passing to the brain, either through 

 the cord or by the cranial nerves, and by the nerves of special 

 sense, as well as those of general sensibility. The stimulus 



