THE EVOLUTION OF MIND 



nervo-muscular apparatus which is the agent of 

 psychical Hfe." Instinct, moreover, implies the 

 coordination of a large number of stimuli with 

 the answering movements, and herein is its chief 

 difference from reflex action, — a difference in 

 degree only. The newly hatched fly-catcher, in 

 seizing a fly, shows " an exact appreciation of 

 distance, as well as a power of precisely regu- 

 lating the muscular movements in accordance 

 with it." The number of impressions and move- 

 ments here coordinated is so considerable that it 

 would take several pages to describe them thor- 

 oughly. Here certain systems of transit lines, 

 involved in the establishment of a correspond- 

 ence in space, are wrought by nutrition in the 

 animal's nervous system so completely that 

 when the outer relation occurs the discharge 

 instantly takes place along the preestablished 

 channels, and the adjustment is made. There 

 is an intricate compounding of reflex actions, 

 involving the assistance of the brain ; for if 

 the cerebellum be sliced, the fly-catching can no 

 longer be performed. Intricate, however, as the 

 combination is, it is a special and unvarying one 

 which has been continually repeated during the 

 whole lifetime of countless ancestral fly-catchers, 

 so that there is nothing strange in the fact that 

 it is completely organized at birth. The prin- 

 ciple is the same as in the simpler phenomena 

 of reflex action. Here, as before, extending the 

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