THE MEANING OF EVOLUTION 285 



Here it seems to us that we find the distinction between 

 the two kinds of bodily activity ; and the distinction 

 is one which depends for its validity on our notions as 

 to what a tool is. An implement made by man is a 

 piece of inert matter fashioned in order that it may 

 be used for a definite preconceived purpose. It has an 

 existence as a definite specific object apart from its 

 use ; and its exercise by the man who made it and its 

 existence in nature are two different things. Its use 

 must be learned, and the results obtained by its employ- 

 ment become more perfect with every repetition of its 

 use. But the mandibles of an insect are implements 

 purposefully adapted for some action or series of 

 actions, just as the pincers of the blacksmith are so 

 adapted. They are, however, implements which are 

 part of the organisation of the animal using them- 

 organised tools and it does not seem as if we ought 

 to think of them, and of their shape and nature, as 

 something apart from their exercise. Must we think 

 of an animal as having to learn how to use any part of 

 its body ? If so, then the problem of instinct remains 

 with us in all its historic obscurity. But if we think 

 of the existence of a bodily tool as something insepar- 

 able from the functioning of the tool, the problem be- 

 comes less obscure, or at least it can be stated in terms 

 of some other problems which we have already con- 

 considered. 



We do actually think of bodily parts or organs as 

 material structures quite apart from the consideration 

 of their functions : it is the distinction between mor- 

 phology and physiology an altogether artificial one. 

 An animal, for the morphologist , is a complex of 

 skeleton, muscles, nerves, glands, and so on ; and it 

 does not matter whether it is contained in a jar of 

 methylated spirit or is running about in a cage. For 



