THE NERVOUS SYSTEM. 117 



educated to discharge so important a duty. While aiding in 

 the development of the mind, let us remember it is necessary 

 to keep the body in a sound state. The various organs must 

 be in a sound condition to perform their proper functions. 

 The body itself must be supplied with the requisite food. 

 The blood must be duly purified by the constant supply of 

 pure air. The muscles must be daily exercised. The skin 

 must be kept clean. In a word, none of the functions of life 

 must be wanting in a healthy performance of their respective 

 duties. To exercise the brain, and pay no regard to the body 

 generally, is sure to result in unhealthy development. This 

 is particularly the case in early childhood. 



All children are not born with the same power for brain 

 development. Some are born without the germs for much 

 future brain power or active intelligence. Others are born 

 with the elements which produce very fertile minds. The 

 careful teacher will discriminate between these two classes, 

 and he will rate the varying grades of capacity in the young 

 under his control. He will be guided by this consideration 

 in directing the mental exercises allotted to each. A bright, 

 active mind requires no urging, and often should be held in 

 restraint ; while the sluggish brain must be stirred by encour- 

 agement and stimulated by example. 



Overwork of a too active brain is sometimes the direct 

 cause of acute disease of that organ, with a fatal termination. 

 In other instances, too much brain-work leads to degenera- 

 tion of the over-grown gray matter, and the promising child 

 becomes sluggish in mind or deficient in intellect, and even 

 in some cases an idiot. It must never be forgotten that 

 physical exercise is just as important to the growing child 

 as brain-work, and in many cases more so. When a quick, 

 clever child becomes indifferent to play, and prefers to sit in 

 dreamy idleness, his brain is not in a healthy condition, and 



