THE NERVOUS SYSTEM. 185 



tion. They are automatons, or creatures of necessity. 

 In the higlier animals certain actions are automatic, as 

 breathing, the beating of the heart, the contractions of 

 the iris, and all the first movements of an infant." But, 

 generally, the actions of animals are not the result of mere 

 bodily organization. 



The inferior orders are under the control of Instinct, 

 i. e., an apparently untaught ability to perform actions 

 which are useful to the animal."" They seem to be born 

 with a measure of knowledge and skill (as Man is said to 

 have innate ideas), acquired neither by reason nor experi- 

 ment. For what could have led Bees to imagine that by 

 feeding a worker -larva with royal jelly, instead of bee- 

 bread, it would turn out a queen, instead of a neuter? 

 In this case, neither the habit nor the experience could be 

 inherited, for the worker -bees are sterile. AVe can only 

 guess that the discovery has been communicated by the 

 survivors of an older swarm. Uniformity is another char- 

 acteristic feature of instinct. Different individuals of the 

 same species execute precisely the same movements under 

 like circumstances. The career of one Bee is the career 

 of any other. We do not find one clever and anot])er 

 stupid. Honey-combs are built now as they were before 

 the Christian era. The creatures of pure instinct appear 

 to be tied down, by the constitution of their nervous sys- 

 tem, to one line of action, from which they cannot spon- 

 taneously depart. The actions vary only as the structure 

 changes."' There is a wonderful fitness in what they do, 

 but there is no intentional adaptation of means to ends. 



All animals, from the Star-fisii to Man, are guided more 

 or less by instinct; but the best examples are furnished 

 by the insect-world, especially by the social Hymenopters 

 (Ants, Bees, and Wasps). The Butterfly carefully pro- 

 vides for its young, which it is destined never to see ; 

 many Insects feed on particular species of plants, which 



