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114 WHAT IS LIFE 



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thus is responsive to the most manifold expressions 

 of life. In the machine power is developed in a 

 ; restricted direction, in the organism there is an ex- 

 traordinarily free, many-sided play of powers. 



A comparison will make the difference between 

 the two more obvious. Look at the difference 



between a musical box or a gramophone and the 

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human larynx combined with the lungs and the 



nerves and muscles which set it in operation. 

 Both of these can give vent to numerous tunes and 

 those of all kinds. But the difference between 

 them is enormous. The instrument can only play 





the tune or tunes which it is constructed to play 

 ' or the records which are inserted into it. On the 

 other hand, without any visible change the human 

 larnyx can pass from one melody to another and 

 alter its tune and time by the action of the muscles 

 under the influence of the will of the individual 

 who is singing. Moreover, at will the singer can 

 alter the pitch, the time and the tone of his song, 

 introduce all sorts of trills and runs and modifica- 

 tions which the instrument can never do, for that 

 must always perform its task in exactly the same 

 manner. 



Then we come to a second difference. When, 

 as the result of a stimulus, changes have taken 

 place in the organism, say that a muscle has be- 

 come altered in structure and tired by long use, it 



