INTRODUCTION. II 



series of actions it contracts a habit; the repetition 

 may be so frequent that the animal comes to 

 accomplish it without knowing it ; the brain no 

 longer intervenes ; the spinal cord or the chain of 

 ganglia alone govern this order of acts, to which has 

 been given the name of reflex actions. A reflex may 

 be so powerful as to be transmitted by heredity to 

 the descendants ; it then becomes an instinct. 



Thus by its nature instinct does not differ from 

 intelligence, but is intimately connected with it by a 

 chain of which all the links may be counted. The most 

 intelligent of beings, Man, performs actions that are 

 purely mechanical ; many indeed can with justice be 

 called instinctive ; and, on the other hand, an animal 

 for whom an innate hereditary instinct is sufficient in 

 ordinary life will give proof of intelligence and re- 

 flection if circumstances in which his instinct is 

 generally efficacious become modified so that he can 

 no longer profit by them. Among other ingenious 

 experiments to show the supposed difference between 

 instinctive and reflective acts, Fabre brings forward 

 the following ^ : — The Chalicodoma, a hymenopterous 

 relative of the Bees, constructs nests composed of cells 

 formed of mud agglutinated with saliva. The cell once 

 constructed, the insect begins to fill it with honey before 

 laying an egg there. He returns with his booty and 

 wishes to disburse himself in the nest, finds the cellule 

 which he has to fill, and proceeds always in the same 

 order : first, he plunges his head in the cell and dis- 

 gorges the honey which fills his crop; secondly, he 

 emerges from the cell, turns round, and lets fall the 

 pollen which remains attached to his legs. Suppose 



1 J. H. Fabre, Souvenirs entomologiques, Paris, 1879, pp. 275 

 et seq. 



