28 INTRODUCTION. 



lity, tliat is, to some few slight movements to escape from pain. 

 Between these two extremes, the degrees are infinite. 



In a great number of animals, however, there exists another 

 kind of intelligence, called instinct. This induces them to 

 certain actions necessary to the preservation of the species, 

 but very often altogether foreign to the apparent wants of the 

 individual ; often also very complicated, and which, if attri- 

 buted to intelligence, would suppose a foresight and know- 

 ledge in the species that perform them infinitely superior to 

 what can possibly be granted. These actions, the result of 

 instinct, are not the effect of imitation, for very frequently the 

 individuals who execute them have never seen them perform- 

 ed by others : they are not proportioned to ordinary intelli- 

 gence, but become more singular, more wise, more disinterest- 

 ed, in proportion as the animals belong to less elevated classes, 

 and in all the rest of their actions are more dull and stupid. 

 They are so entirely the property, of the species, that all its 

 individuals perform them in the same way without ever im- 

 proving them a particle. 



The working bees, for instance, have always constructed 

 very ingenious edifices, agreeably to the rules of the highest 

 geometry, and destined to lodge and nourish a posterity not 

 even their own. The solitary bee, and the wasp also, form 

 highly complicated nests, in which to deposit their eggs. 

 From this egg comes a worm, which has never seen its parent, 

 which is ignorant of the structure of the prison in which it is 

 confined, but which, once metamorphosed, constructs another 

 precisely similar. 



The only method of obtaining a clear idea of instinct, is by 

 admitting the existence of iimate and perpetual images or 

 sensations in the sensorium which cause the animal to act in 

 the same way as ordinary or accidental sensations usually do. 

 It is a kind of perpetual vision or dream that always pursues 

 it, and it may be considered, in all that has relation to its in- 

 stinct, as a kind of somnambulism. 



Instinct has been granted to animals as a supplement to in- 

 telligence, to concur with it, and with strength and fecundity, 

 in the preservation, to a proper degree, of each species. 



