116 ADVANTAGE OF COMBINING MENTAL 



healthful exercise may be thus secured, and every 

 step be made to add to useful knowledge and to in- 

 dividual enjoyment. The botanist, the geologist, 

 and the natural historian experience pleasures in 

 their walks and rambles of which, from disuse 

 of their eyes and observing powers, the multitude 

 is deprived. This truth is acted upon by many 

 teachers in Germany. In our own country, too, it 

 is beginning to be felt, and one of the professed 

 objects of infant education is to correct the omis- 

 sion. It must not, however, be supposed that any 

 kind of mental activity will give the necessary 

 stimulus to muscular action, and that, in walking, it 

 will do equally well to read a book or carry on a 

 train of abstract thinking, as to seek the necessary 

 nervous stimulus in picking up plants, hammering 

 rocks, or engaging in games. This were a great 

 mistake ; for in such cases the nervous impulse is 

 opposed rather than favourable to muscular action. 

 Wherever the mind is absorbed in reading or in 

 abstract speculation, the active will to set the 

 muscles in motion must necessarily be proportion- 

 ally weakened, and the action of the muscles be re- 

 duced to that inanimate kind I have already con- 

 demned as almost useless. For true and beneficial 

 exercise, there must be harmony of action between the 

 moving power and the part to be moved. The will and 

 the muscle must be both directed to the same end and at 

 the same time, otherwise the effect will be imperfect. 

 The force exerted by strong muscles, animated by 

 strong nervous impulse or will, is prodigiously 

 greater than when the impulse is weak; and as 

 man was made not to do two things at once, but to 

 direct his whole powers to the one thing he is per- 

 forming at the time, he has ever excelled most when 

 he followed this law of his nature. 



When a physician urges the necessity of exercise, 

 it is very usual for him to be told by persons of an 

 indolent or sedentary habit, that even a short walk 



