322 ADVANCED PHYSIOLOGY 



down because of excessive mental work resulting in nervous 

 strain. Since such a condition is very unfortunate and very 

 serious, it is important to learn what causes contribute to it. 



In the first place we may be confident that only in very 

 rare cases is the trouble due to overwork, or to excessive study. 

 The brain gains strength by use, and even a very hard student 

 is not likely to use it too severely, if he is otherwise in proper 

 health. If the brain is treated reasonably, and the whole 

 body kept in a state of health, the brain may work very 

 hard and grow stronger all the time. But the person who is 

 fond of study is apt to neglect entirely the other functions of 

 his body, and allow his muscles and other organs to lack 

 proper exercise. Exercise, especially in fresh air to produce 

 vigorous respiration, helps to keep the brain alert. The 

 student perhaps fails to use proper discretion in his diet; 

 overeating, irregular eating and too rich foods throw his 

 body out of condition. The brain needs good wholesome 

 food to keep it active, and it is well to remember that there 

 are no special " brain foods," this term being used simply to 

 catch trade for certain food products. The student neglecting 

 some of these plain laws of health, becomes ill and his break- 

 down is apt to be considered due to over-study. 



It is working the brain under improper conditions rather 

 than working it too hard that produces nerve strain. Using 

 the brain excessively without sufficient outdoor exercise, 

 studying late at night when one needs sleep, using it too long 

 upon the same kind of work, are all likely to injure it. Rest 

 and sleep are necessary for an active brain. The amount of 

 sleep needed is not the same for all persons, and growing 

 people require more than adults. In general about eight 

 hours sleep in a day should be taken by every one, and more 

 than this by children. The attempt to study after one has 

 become sleepy is always a mistake; in the first place it is the 

 hardest tax on the brain, and in the second place it is often 

 useless. The brain is not in condition to receive and remem- 



