WHAT IS INTELLIGENCE? 195 



regard to this one movement of the headless dog and frog, 

 Prof. Harris states : "Not only does there seem purpose 

 in this action, but their precision as regard to place aimed 

 at is very striking. There is no haphazard fumbling, as 

 it were, on the part of the muscles, they answer to the 

 message without undue delay and with all due accuracy. 

 Now this adaption or co-ordination must depend on a very 

 perfectly working intra-neural mechanism." 



We now come to another interesting kind of intelli- 

 gence we call habit. We begin practicing certain actions, 

 as walking, riding, and playing a piano and at first every 

 act must be directed by the brain cells, as no particular 

 nerves have been set apart for any such special perform- 

 ance. But as we continue to perform these acts, special 

 nerve centres develop and take charge of the work, until 

 finally, after long practice the work will be performed 

 without much, if any attention whatever, from the brain 

 cells. 



It seems to be the wish of all the cells of the body that 

 the cells of the brain who have charge of the special 

 senses shall not be occupied with other work more than 

 is necessary ; so as soon as is possible, when any special 

 work is required, the organs or limbs soon learn to take 

 charge of the work without requiring any direction to do 

 so by the brain cells. 



You can clearly see the reason for this ; if the party in 

 charge of the periscope of the submarine should have to 

 be occupied continually with directing the performance 

 of details which could be done by others, he could not at- 

 tend to his own work, which should be obtaining infor- 

 mation from the outside world, and directing the more 

 important acts of the boat in its movements of capture 

 and escape. 



^Started out to prove in this chapter that : 



