128 PRESENT-DAY RATIONALISM 



up into slices in grass-blades, it does not require scissors 

 to reduce it to small pieces in order to make a convenient 

 mouthful. But a carnivorous animal has a large lump of 

 flesh in the shape of a carcase. It requires to cut it up. 

 The action of biting in order to do this, previous to its 

 consumption, has converted its teeth into scissors-like 

 carnassials, and as it can no lonrer masticate it bolts 

 the pieces whole. 



So, too, man would never have thought of making 

 scissors unless he had had something that he wanted to 

 cut up. The object induced the manufacture, " Necessity- 

 being the mother of invention ". The parallel is com- 

 plete ; only, in the one case it is spontaneously effected 

 by the plasticity and adaptability of living matter ; in the 

 other it is artificially produced by the consciousness and 

 skill of man. 



Not only, then, do we recognise finality in the func- 

 tions of the completed organs, but in the very formations 

 of the organs themselves. 



But now, asks M. Janet, " Is this analogy between 

 human industry and the industry of Nature, though 

 justified by theory, also justified by science ? " Accord- 

 ing to the older methods of interpretation, the form of 

 the organs was supposed to imply their function, l^ut at 

 the present day we have reason to believe the reverse, 

 or, as I have expressed it, W\7[.\. function prccedes^stnictuic. 

 In generalised animals different functions are often 

 executed by one and the same organ ; and it is not till 

 later — i.e., higher in the scale of life — that differentiation 

 of a common structure into special organs occurs, each 

 organ now taking on its special function, according to 

 the principle of the division of labour. 



The present method of investigation does not limit 

 itself to organs, but presses on to the ultimate analysis, 



