396 



COMPARATIVE ZOOLOGY 



an infant. 153 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. 154 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 experiment. For what could have led bees to 

 imagine that by feeding a worker larva with royal jelly, 

 instead of beebread, 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. We can only guess that the discovery has been 

 communicated by the survivors of an older swarm. 

 Uniformity is another characteristic feature of instinct. 

 Different individuals of the same species execute pre- 

 cisely the same movements under like circumstances. 

 The career of one bee is the career of another. We do 

 not find one clever and another stupid. Honeycombs 

 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 system, to one line 

 of action, from which they can not spontaneously depart. 

 The actions vary only as the structure changes. 155 There 

 is a wonderful fitness in what they do, but there is no 

 intentional adaptation of means to ends. 



All animals, from the starfish to man, are guided more 

 or less by instinct ; but the best examples are furnished 

 by the insect world, especially by the social hymenop- 

 ters (ants, bees, and wasps). The butterfly carefully 

 provides for its young, which it is destined never to 

 see ; many insects feed on particular species of plants, 

 which they select with wonderful sagacity ; and monkeys 

 avoid poisonous berries ; bees and squirrels store up 

 food for the future ; bees, wasps, and spiders construct 



