ANIMAL AND RATIONAL INTELLIGENCE 157 



intelligence. As it is impossible from superiority of 

 sensory apparatus, and correlative superiority in brain 

 structure, toTnfer intelligence, so is it impossible from 

 approximation of structure in the higher mammals to 

 argue towards similarity of intelligence. 



What holds true of superiority of sensory apparatus, 

 holds of superiority in brain structure. These are cor 

 related. Whenever sensory apparatus is superior, there 

 brain structure is correspondingly so. Hence Darwin s 

 saying, The brain of an ant is one of the most mar 

 vellous atoms of matter in the world, perhaps more 

 so than the brain of a man. l What the brain of an 

 ant does, is to provide for the functional activity of the 

 marvellous differentiated sensory structure appearing 

 in the antennas, or jointed feelers, projecting from the 

 head ; and further, to co-ordinate impressions received 

 by these feelers, so as to direct the activity of the life. 

 This is true of the ant, just as it is true of the func 

 tions of brain in every case. 2 The same functions are 

 fulfilled by the brain in the life of the dog, and in 

 the life of man. All brains are alike in this, that they 

 provide for functional activity of sensory and of motor 

 apparatus ; and that they co-ordinate impressions in 

 such a manner as to provide for bodily activity. The 

 brain of the ant is marvellous as compared with that 

 of the dog. When next the resemblance of the dog s 

 brain to man s brain is considered ; and the still closer 

 resemblance of the ape s brain to the human brain ; 

 and when, further, the contrasts of these three are 

 considered, it does not appear that w T e can account 

 structurally for the superior intelligence of the dog. 



This seriously affects the validity of Darwin s infer- 



1 Descent of Man, p. 54. 2 Ibid., p. 6. 



