EDUCATION. 101 



mental work millions of grey cells are left unused; 

 but these cells are not independent, self-sustaining, 

 self-acting cells. Nerve force, pure blood, oxygen, 

 form a definite and limited sum-total, not in the young 

 only but in all ages. It is not thinking only that 

 exhausts thinking nerve; the convertibility of nerve 

 force goes much further. Powerful emotion destroys 

 thought; deep thought destroys emotion. Excessive 

 muscular force (notwithstanding that motor nerve- 

 entres are more or less isolated centres) impairs both 

 thought and feeling. 



What then (the question comes home to everyone) 

 is a given individual nervous organisation capable of 

 doing ? Let us look first at nerve inheritance. If no 

 tendency to nerve ailment is inherited, and especially 

 if none exists on the parental side which the individual 

 follows, if no accident has intervened in the trans- 

 mission of nerve or in its training, the child may be 

 set to work the adult to hard work so long as this 

 is free from emotional worry. But not otherwise. 

 Nothing approaching to strain must be put on the 

 brain which inherits trouble or weakness, or which 

 has been subjected to unfavourable circumstance. The 

 outward bodily appearance is altogether misleading. 

 To stout limbs and red cheeks there may be joined 

 a nervous system quite incapable of effort. While 

 within a pale skin and delicate frame there may be a 

 brain which close and continued labour cannot easily 

 injure. 



A knowledge of hereditary and physiological pecu- 

 liarities is of incalculable benefit and in many ways. 

 One boy (or girl) inherits silent nerve ; he should be 

 encouraged to make little speeches. Another boy 

 inherits voluble nerve ; he should be taught, in some 



