326 COORDINATION AND SENSATION 



greater number and variety of nerve stimuli. Self-control 

 means the ability to suppress activities that would result 

 from undesirable stimuli and to direct the bodily activities 

 into channels that are profitable. Self-control, therefore, is 

 not only to be exercised on occasions of great emergency, 

 but in the everyday affairs of life as well. It is even more 

 important that the daily toiler at his task be able to keep 

 the petty annoyances of life from acting as irritants to his 

 nervous system than that he keep cool during some great 

 calamity. The habit of self-control is acquired mainly 

 through the persistent effort to prevent any and all kinds 

 of petty annoyances from affecting the nerves or the 

 temper. 



Nervousness. Self-control is much more easily prac- 

 ticed by some than by others. This is due partly to habit, 

 but is also due to an actual difference in the degree of 

 sensitiveness, or irritability, of the nervous systems of dif- 

 ferent people. One whose nervous system tends to respond 

 too readily to any and all kinds of stimuli is said to be 

 " nervous." This condition is in some instances inherited, 

 but is in most cases due to the wasteful expenditure of 

 nervous energy or to the action of some drug upon the 

 body. Excess of mental work, too much reading, long- 

 continued anxiety, eye strain, and the use of tea, coffee, 

 alcohol, tobacco, or other drugs, including many of those 

 taken as medicines, are known to cause nervousness. 

 Nervousness is not only a source of great annoyance, both 

 to one's self and to others, but is a menace to the general 

 health. 



The first step toward securing relief from such a con- 

 dition is the removal of the cause. The habits should be 

 inquired into and excesses of all kinds discontinued. In 

 some instances it may be necessary to have the eyes exam- 



