BRAIN AND NERVOUS SYSTEM. 365 



of education, a contrary principle is often adopted, and the 

 strong faculties are made stronger and the weak weaker. 

 Progress and acquirement seem to be the great object with 

 some, and therefore they apply the main force of their minds 

 to the subjects in which they make the easiest and most rapid 

 advancement. If they have a taste for, or an extraordinary 

 power of understanding, music, mathematics, mechanics, or 

 general affairs, they give their attention to them, and neglect 

 the others, for which they have less taste, and which they 

 learn with difficulty. 



843. Whatever may be the cause that only a part of the 

 faculties are exercised, and the others dormant, it is certain 

 that those which are in active employment will be quick and 

 comparatively strong, and give pleasure when in action, 

 while the others are slow and weak, and act unwillingly, and 

 even with pain. If the whole force of the brain has been 

 directed to the cultivation or the action of one or a few 

 faculties, the dulness and weakness of the others are about 

 in proportion to the energy and activity of these. Hence, in 

 the division of labor, a man becomes a more perfect work- 

 man within his narrow sphere; but his range of knowledge 

 is limited. 



844. Some men learn and perform, during their whole 

 lives, only one operation in the mechanic arts. In this lim- 

 ited sphere of action, they show exquisite workmanship ; but 

 beyond this they have neither knowledge nor power, and in 

 the subjects of general interest they manifest great weakness 

 and inactivity of intellect. In the manufacture of pins there 

 were formerly twenty processes, and a man performed only 

 one of these. From the beginning to the end of his working 

 life, he exercised only the faculty of making one twentieth 

 part of a pin, and if required to do any other work, or attend 

 to any other subject of thought, he did it unskilfully, and 

 with reluctance. 



845. The same is shown in the intellectual processes. 

 Some men cultivate their memory to a remarkable degree, 

 without a corresponding cultivation of the reasoning powers. 



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