28 INTRODUCTION. 
lity, that 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 innate 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. 
[t is a kind of perpetual vision or dream that always pecs 
it, and it may be considered, in all that has relation tov its in- 
stinct, as a kind of somnambulism. nigh gy MY 
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. - 
