ii INTELLIGENCE AND INSTINCT 147 



come under it. But this definition, like that which we 

 have provisionally given of intelligence, determines at 

 least the ideal limit toward which the very numerous 

 forms of instinct are travelling. Indeed, it has often 

 been pointed out that most instincts are only the con 

 tinuance, or rather the consummation, of the work of 

 organization itself. Where does the activity of instinct 



begin ? and where does that of nature end ? We 



o 



cannot tell. In the metamorphoses of the larva into 

 the nymph and into the perfect insect, metamorphoses 

 that often require appropriate action and a kind of 

 initiative on the part of the larva, there is no sharp line 

 of demarcation between the instinct of the animal and 

 the organizing work of living matter. We may 

 say, as we will, either that instinct organizes the 

 instruments it is about to use, or that the process of 

 organization is continued in the instinct that has to use 

 the organ. The most marvellous instincts of the insect 

 do nothing but develop its special structure into move 

 ments : indeed, where social life divides the labour 

 among different individuals and thus allots them differ 

 ent instincts, a corresponding difference of structure is 

 observed : the polymorphism of ants, bees, wasps and 

 certain pseudoneuroptera is well known. Thus, if we 

 consider only those typical cases in which the complete 

 triumph of intelligence and of instinct is seen, we 

 find this essential difference between them : instinct 

 perfected is a faculty of using and even of constructing 

 organized instruments ; intelligence -perfected is the faculty 

 of making and using unorganized instruments. 



The advantages and drawbacks of these two modes 

 of activity are obvious. Instinct finds the appropriate 

 instrument at hand : this instrument, which makes 

 and repairs itself, which presents, like all the works of 



