INFLUENCES WHICH AFFECT THE MIND 309 



559. Change of occupation. When one set of brain cells 

 has become tired, it is well to direct the thoughts to another 

 subject and let the first set of cells rest. It is a relief to 

 study a history lesson after working hard at arithmetic 

 problems. A change of occupation is the best kind of 

 rest. It is well to alternate pure brain work with work 

 which, like gardening and carpentering, requires muscular 

 effort 



560. Healthy bodies. The brain depends upon the blood and 

 digestive organs for the power with which to work. When any of the 

 organs are acting improperly the brain is the first to suffer. The strong- 

 est brains are contained in the healthiest bodies. No kind of food is 

 brain food more than another, but fish and phosphates are hardly so 

 valuable as beefsteak and salt. 



561. Exercise and brain work. Muscular exercise is needed 

 to keep the body in the best physical condition. Thus it makes the 

 brain stronger. It also takes some blood which otherwise would con- 

 tinue to circulate in the Drain, and thus it rests the mind after work. 



If exercise is continued until the body is tired, no energy is left for 

 the brain, but sleep comes on as soon as the body composes itself for 

 brain work. Exercise for the benefit of the brain should be brisk in 

 order to produce the best effect upon the circulation of the blood, but 

 it should never be carried to the point of fatigue. 



562. Nervousness. When the brain is exhausted from 

 overwork or from worry, it has not enough energy to con- 

 trol itself or the reflex actions of the spinal cord. Slight 

 and strong sensations are equally unpleasant, and the 

 effort to control the feelings seems to increase the suffer- 

 ing. Thus there arises a condition called nervousness. 



Nervousness is a lack of self-control. The judicious ex- 

 pression of sympathy by a strong-willed person is the best 

 means of overcoming it. On the other hand, sarcasm and 

 scolding only do injury and increase the nervousness. 



563. Hysteria. An extreme lack of self-control is called 



