tude, forced to
continually busy itself with providing for its needs, remains
permanently deprived of the knowledge which it should acquire; in
general, exercises to a very slight extent the organ of its
intelligence; preserves and propagates a multitude of prejudices
which enslave it, and cannot be as happy as those who, guiding it,
are themselves guided by reason and justice.

"As to the animals, besides the fact that they in descending order
have the brain less developed, they are otherwise proportionally
more limited in the means of exercising and of varying their
intellectual processes. They each exercise them only on a single or
on some special points, on which they become more or less expert
according to their species. And while their degree of organization
remains the same and the nature of their needs (_besoins_) does not
vary, they can never extend the scope of their intelligence, nor
apply it to other objects than to those which are related to their
ordinary needs.

"Some among them, whose structure is a little more perfect than in
others, have also greater means of varying and extending their
intellectual faculties; but it is always within limits circumscribed
by their necessities and habits.

"The power of habit which is found to be still so great in man,
especially in one who has but slightly exercised the organ of his
thought, is among animals almost insurmountable while their physical
state remains the same. Nothing compels them to vary their powers,
because they suffice for their wants and these require no change.
Hence it is constantly the same objects which exercise their degree
of intelligence, and it results that these actions are always the
same in each species.

"The sole acts of variation, _i.e._, the only acts which rise above
the limits of habits, and which we see performed in animals whose
organization allows them to, are _acts of imitation_. I only speak
of actions which they perform voluntarily or freely (_actions qu'ils
font de leur plein gre_).

"Birds, very limited in this respect in the powers which their
structure furnishes, can only perform acts of imitation with their
vocal organ; this organ, by their habitual efforts to render the
sounds, and to vary them, becomes in them very perfect. Thus we know
that several birds (the parrot, starling, raven, jay, magpie, canary
bird, etc.) imitate the sounds the