210 FWNCTIONS OF THE BRAIN. 



stant relation between mental power and develop- 

 ment of brain. It not only explains why capacities 

 and dispositions are so different, but shows incon- 

 trovertibly that the cultivation of the moral and in- 

 tellectual faculties can be successfully carried on 

 only by acting in obedience to the laws of organiza- 

 tion, and associating together those faculties, the 

 organs of which are simultaneously progressive in 

 their growth. It is a law, for instance, that alter- 

 nate periods of activity and repose conduce to the 

 strength and development of every organ, and to the 

 easy performance of its function, and that excess in 

 either is alike hurtful in its consequences. If, there- 

 foie, in our anxiety for the advancement of a child 

 in a favourite pursuit, we urge it to incessant and 

 unvaried exertion of the same kind for many hours 

 a day, we violate this law in neglecting the neces- 

 sary intervals of rest, and thus run the risk of injur- 

 ing the health of the brain, and entirely defeating 

 our object. And, on the other hand, if we withdraw 

 the child altogether from the pursuit, for weeks or 

 months at a time, as happens during the vacation of 

 a school, we violate the law again, in depriving the 

 faculties of their necessary exercise, and thus run 

 the risk of sacrificing the improvement already 

 gained, and of diminishing the mental power. In 

 neither case is the brain exercised in conformity 

 with the organic laws, and consequently we look in 

 vain for the same amount of improvement which 

 would have followed their fulfilment ; and yet, so far 

 ^s the physiology of the brain from being considered 

 as the only sound basis on which the science of 

 education can rest, that very few teachers or moral- 

 ists are aware that the organic laws have any con- 

 nexion with the operations of mind, and still fewer 

 have ever thought of adapting their practice to the 

 dictates of these laws ; although no truth in educa- 

 tion or philosophy can be more clearly proved, or 



