332 LAMARCK, HIS LIFE AND WORK 
system,* have perceptions of objects which affect 
them, and seem to have memory of them when they 
are repeated. Yet they can vary their actions and 
change their habits, though they do not possess the 
organ whose acts could give them the means. 
“ On the Instincts of Animals. 
“We define zzstznct as the sum (ensemble) of the 
decisions (determinations) of animals in their actions; 
and, indeed, some have thought that these determi- 
nations were the product of a rational choice, and 
consequently the fruit of experience. Others, says 
Cabanis, may think with the observers of all ages that 
several of these decisions should not be ascribed to 
any kind of reasoning, and that, without ceasing as 
for that to have their source in phy sical sensibility, 
they are most often formed without the will of the 
individuals able to have any other part than in better 
directing the execution. It should be added, without 
the will having any part in it; for when it does not 
act, it does not, of course, direct the execution. 
“If it had been considered that all the animals 
which enjoy the power of sensation have their inner 
feeling susceptible of being aroused by their needs, 
and that the movements of their nervous fluids, which 
result from these emotions, are constantly directed 
by this inner sentiment and by habits, then it has 
been felt that in all the animals deprived of intelli- 
gence all the decisions of action can never be the re- 
sult of a rational choice, of judgment, of profitable 
experience—in a word, of will—but that they are 
subjected to needs which certain sensations excite, 
and which awaken the inclinations which urge them 
on. 
“Inthe animals even which enjoy the power of 
* Rather a strange view to take, as the brain of insects is now 
known to be nearly as complex as that of mammals. 
