82 ESSAYS OF A BIOLOGIST 



extended to an unprecedented degree both in space 

 and time, so tools represent, biologically speaking, an 

 extension of himself as an operator. While man is 

 using a tool, he and the tool together constitute but 

 a single unit in the struggle for existence. As various 

 writers have put it, tools and machines are temporary 

 organs of man, which have the additional merit of 

 being replaceable if lost or damaged. 



But this is not all : the great power of association 

 possessed by man, together with his faculty of general- 

 ization and of speech, makes it possible for him to 

 learn his role in the community, instead of being born 

 with it as are the bee and the ant. Great educability 

 instead of differentiated instinct, infinite possibility, 

 at the expense of the pains of learning, instead of an 

 effortless but limited stock of inborn modes of be- 

 haviour — in this again man represents a qualitatively 

 new organic type. 



By this means he can escape what has always been 

 a necessity with lower forms : by means of education 

 and machinery he can play a specialized part in the 

 community life, and so build up a community with a 

 high degree of division of labour, without being born 

 specialized. He could not thus learn his role if he 

 were not educable, nor if he could not manufacture 

 tools. An ant or a duck or a dog possesses admirable 

 tools for its particular job : but they are living parts 

 of the organism's own body. A worker ant cannot 

 lay down its serviceable carpentering mandibles and 



