THE BRAIN 299 



speak and write correct answers to questions, but cannot read and un- 

 derstand what he has just written. Sometimes a person cannot speak 

 his thoughts, but can read aloud what he has written. Careful observa- 

 tion of the speech is of great value in locating brain diseases, for the 

 speech centers involve nearly every region of the brain. 



543. The Intellect. The cerebral cells act in as definite 

 and uniform ways as the cells of the intestine or heart, and 

 men studied the laws of their minds long before the struc- 

 ture or even the existence of cells was known. The actions 

 of the mind are divided into three great divisions. First, 

 is the intellect, or the pure knowledge-gaining faculty. This 

 includes the work of all the sensory regions of the brain 

 and such a part of the frontal regions as is concerned in 

 receiving knowledge through speech. It is the basis of the 

 other mental acts. 



544. The sensibilities. The second division of mind 

 study comprises the sensibilities, or the feelings. Much 

 of knowledge does not concern us in the least. All feeling 

 is based on knowledge, and all knowledge leads up to 

 feeling as we come to know a thing intimately. We love 

 it or hate it, and are sorry for its loss. 



545. The will. The third and highest act of the mind 

 is to will to do. It is the control which the frontal region 

 has of the motor region. In order to do a thing we must 

 first have knowledge, and, second, we must feel some degree 

 of emotion or desire to do it. Only a small part of knowl- 

 edge causes feeling or emotion, and only a small part of 

 even our strong feelings are expressed in action. 



Of all the actions of the mind the will is the most difficult to arouse 

 and control. Since it depends upon feeling, this faculty must first be 

 aroused. Men readily act their feelings of anger and fear. To form a 

 new will, active and brave, which is capable of controlling the natural 

 and acquired appetites and passions, is the highest and noblest work 

 of man. 



