I30 THE ASCENT OF MAN 



By no means. And yet it is probable for other 

 reasons that the ultimate Hand has appeared ; 

 that there will never be a more perfectly handed 

 animal than Man. And why? Because the causes 

 which up to this point have furthered the evolu- 

 tion of the Hand have begun to cease to- act. In 

 the perfecting of the bodily organs, as of all other 

 mechanical devices, necessity is the mother of inven- 

 tion. As the Hand was given more and more to 

 do, it became more and more adapted to its work. 

 Up to a point, it responded directly to each new 

 duty that was laid upon it. But only up to a 

 point. There came a time when the necessities 

 became too numerous and too varied for adaptation 

 to keep pace with them. And the fatal day came, 

 the fatal day for the Hand, when he who bore it 

 made a new discovery. It was the discovery of 

 Tools. Henceforth what the Hand used to do, and 

 was slowly becoming adapted to do better, was to 

 be done by external appliances. So that if anything 

 new arose to be done, or to be better done, it was 

 not a better Hand that was now made but a better 

 tool. Tools are external Hands. Levers are the 

 extensions of the bones of the arm. Hammers are 

 callous substitutes for the fist. Knives do the work 

 of nails. The vice and the pincers replace the fin- 

 gers. The day that Cave-man first split the marrow 



