CHAPTEE XLVIII 



FUNCTIONS OF THE CEREBRUM 



THE brain is the seat of those psychical or mental processes which 

 are called volition and feeling ; volition is the starting-point in motor 

 activity ; feeling is the final phase of sensory impressions. 



In the days of the ancients very curious ideas prevailed as to 

 the use of the brain. It is true that Alkmiion, as early as 580 B.C., 

 placed the seat of consciousness in the brain, but this view was of 

 the nature of a guess, and did not meet with general acceptance ; 

 and two hundred years later Aristotle considered that the principal 

 use of the brain was to cool the hot vapours rising from the heart. 

 At this time the seat of mental processes, especially those of an 

 emotional kind, was supposed to be in the heart, an idea now con- 

 fined to poets ; or in the bowels, as those acquainted with such ancient 

 writings as the Bible will know. 



As time went on, truer notions regarding the brain came to the 

 fore : thus Herophilus (300 B.C.) was aware of the danger attending 

 injury to the medulla; Aretaeus and Cassius (97 A.D.) knew that 

 injury to one side of the brain produced paralysis of the opposite 

 side of the body ; and Galen (131 203 A.D.) was acquainted with the 

 main motor and sensory tracts in brain and cord. Between that 

 time and this, most of the celebrated anatomists have contributed 

 something to our knowledge, and one may particularly mention 

 Vesalius, Sylvius, Eolando, Gall, Cams, Willis, and Burdach ; many 

 of these names are familiar because certain structures in the brain 

 have been christened after them. The erroneous notion that the 

 brain was not excitable by stimuli lasted even to the days of 

 Flourens and Magendie. 



Effects of Removal of the Cerebrum. 



When the brain is removed in a frog, it is deprived of volition 

 and of feeling ; it remains perfectly quiescent unless stimulated ; it 

 is entirely devoid of initiatory power, but, as we have already seen, 

 it will execute reflex actions, many of which are of a complex nature 

 (see p. 669 and also Chapter L.). 



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