THE EDUCATION OF THE NERVOUS SYSTEM. 343 



surrounding conditions influencing growth. The average 

 individual is first subjected to some formal training when 

 about three years of age. At this time the number of 

 cell elements is complete, and the history of future organi- 

 sation has been in its broad outlines determined by their 

 first arrangement. Examination shows that but a fraction 

 of the elements have begun to develop, though growth 

 is everywhere visible, and some of the elements have 

 attained almost their full size. The encephalon at this 

 age has more than two-thirds its adult weight. It is 

 during this last stage of the growing period, which to be 

 sure may continue into the forties, that formal educa- 

 tion is called upon to modify the central system. In 

 these pages it has been maintained that this modification 

 might go on without great increase in weight, though 

 with much effect on the organisation, because although 

 in many cases the nerve elements were in the granule 

 stage of development and without prolongations, yet in 

 many others they possessed prolongations which had 

 taken all but the last step necessary to the establish- 

 ment of full functional connection with neighbouring 

 cells, and hence for such cells the constructional change 

 demanded was very small. The impulse to this change 

 in any part of the system is seen to be the improved 

 circulation, giving a larger nutritive supply, and the 

 direct action of the nerve impulses putting the cells in a 

 chemical condition to best make use of the surrounding 

 nutriment. Such being the conditions, two things must 

 happen. Education must fail to produce any funda- 

 mental changes in the nervous organisation, but to some 

 extent it can strengthen formed structures by exercise, 

 and in part waken into activity the unorganised remnant 

 of the dormant cells. No amount of cultivation will 

 give good growth where the nerve cells are few and ill- 

 nourished, but careful culture can do much where there 



