106 A Century of Science 



or four weeks or so he would get up, and begin 

 taking hold of something and pushing it around, 

 just as children push a chair ; and he went through 

 a period of staring at his hands, as human babies 

 do, and altogether was a good deal slower in get- 

 ting to the point where he could take care of him- 

 self. And while I was reading of that I thought, 

 Dear me ! if there is any one thing in which the 

 human race is signally distinguished from other 

 mammals, it is in the enormous duration of their 

 infancy ; but it is a point that I do not recollect 

 ever seeing any naturalist so much as allude to. 



It happened at just that time that I was mak- 

 ing researches in psychology about the organization 

 of experiences, the way in which conscious intel- 

 ligent action can pass down into quasi-automatic 

 action, the generation of instincts, and various 

 allied questions ; and I thought, Can it be that the 

 increase of intelligence in an animal, if carried 

 beyond a certain point, must necessarily result in 

 prolongation of the period of infancy, must 

 necessarily result in the birth of the mammal at a 

 less developed stage, leaving something to be done, 

 leaving a good deal to be done, after birth ? And 

 then the argument seemed to come along very 

 naturally, that for every action of life, every adjust- 

 ment which a creature makes in life, whether a 



