INFLUENCES WHICH AFFECT THE MIND 307 



acquire them. The son of a criminal has a natural 

 tendency to become a criminal, and even if he is well 

 brought up in an upright family he will be far more likely 

 to yield to temptation than a well-born child. Children of 

 educated parents take naturally to study. Children of 

 excitable and nervous parents will also inherit their 

 disposition. By education, natural tendencies of mind and 

 character can be overcome. If a wrong tendency is known 

 and is not .corrected, the blame for future action of the 

 child will lie with his educators rather than with the man. 



555. Unconscious mind action. When the mind is intensely 

 occupied it may not take note of severe sensory impressions. Thus 

 soldiers in battle often fight on, unconscious of severe wounds. You 

 may try in vain to recall a name. Later, when you are thinking of 

 something else, the name may flash into your mind. You may strive 

 to direct the mind to a lesson, but thoughts of a sick friend may persist 

 in arising, and may shut out all thoughts connected with the study. In 

 acquiring any new thought the mind must reason by conscious efforts, 

 step by step, until the idea is clearly in view. Ever afterward the mind 

 may reason out the steps unconsciously and almost instantly, so that we 

 may lose sight of the complexity of the mental processes involved in 

 forming the idea. Learning to perform any mental process is essen- 

 tially becoming able to do it with little or no conscious effort. Then 

 the mind, relieved of the conscious direction of thoughts already 

 learned, is free to acquire new ones. Man is probably unconscious 

 of most of the steps in his mental processes. 



556. Sleep. It is as impossible for the mind to put 

 forth conscious effort continually as it is for the mus- 

 cles. A rest from conscious effort is called sleep. As a 

 rule, a man needs about seven or eight hours of good 

 sleep ; a boy of sixteen needs nine or ten hours, while one 

 of six needs twelve. Sleep should be regular, so that the 

 brain may not become excessively tired between times. 

 As a general rule, an early hour both for going to bed and 



