THE HISTORY OF MENTAL DEVELOPMENT 119 



The child at kindergarten receives a few blocks. It 

 admires and plays with them. Then it is taught to 

 notice their form. After a time it arranges them in 

 groups and learns the first elements of number. But 

 when it has advanced to higher mathematics, the 

 blocks, or figures on the blackboard, become only sym- 

 bols or means of illustrating the great theorems and 

 propositions of that science. Thus the animal has be- 

 gun in the kindergarten way to dimly perceive that 

 there are real, though intangible and invisible, relations 

 between objects. But what is all human science but 

 the clearer vision, and farther search into, and tracing 

 of these same relations ? And what is all advance of 

 knowledge but a perception of ever subtler relations ? 

 What is even the knowledge of right but the perception 

 of the subtlest and deepest and widest relations of man 

 to his environment ? The animal seems to be steadily 

 advancing along the path toward the perception of ab- 

 stract truth, though man alone really attains it. 



And the higher power of association and inference 

 which we call understanding, aided by memory, results 

 in the power of learning by experience, so characteris- 

 tic of higher vertebrates. The hunted bird or mammal 

 very quickly becomes wary. A new trap catches more 

 than a better old one until the animals have learned to 

 understand it, and young animals are trapped more 

 easily than old. Cases showing the limitations of 

 mammalian intelligence are interesting in this connec- 

 tion. A cat which wished to look out and find the 

 cause of a noise outside, when all the windows were 

 closed by wooden blinds, jumped upon a stand and 

 looked into a mirror. Her inference as to the general 

 use of glass was correct ; all its uses had not yet come 



