208 EVOLUTION AND MAN S PLACE IN NATURE 



account for what has happened without granting that 

 the sign has been interpreted. This conclusion is 

 confirmed by reference to multiplication of signs for 

 direction of the same line of conduct. A whistle 

 may arrest a dog, but a sign, visible or audible, will 

 direct his action. Our conclusion is further sustained 

 by reference to the significance of sound as deter 

 mined by the usage of the master. Go home/ will 

 send one dog back, but the Gaelic equivalent alone 

 will be effective in the case of a dog reared in the 

 Highlands of Scotland where the Celtic tongue is in 

 common use. Observation affords ample testimony 

 for this. If we decide on the lines of action to be 

 followed, keeping by uniform signs for direction, the 

 higher animals are capable of interpreting signs, 

 readily attaining fixed associations, and performing 

 the work required. 



Beyond this, habit may accomplish much. Under 

 this law, action may sink into mechanical routine, 

 just as happens with ourselves. But if intelligence 

 is to be used so as to secure development of the 

 faculty, the whole interest of animal life must be 

 gathered around what is being accomplished. For 

 this, the direct living relation of man and animal 

 must be sustained from day to day, the man giving 

 actual guidance, and the animal feeling that he has 

 some share in the satisfaction following. We can no 

 more reduce an animal to a working machine, and 

 yet secure development of his intelligence, than we 

 can thus secure intellectual advance in the life of a 

 man. Jog-trot in harness accomplishes little for the 

 horse, hoAvever much it does for the owner. The load 

 of stones may arrive at the proper destination, but 



