e
the direct effect is given to changed actions in consequence of changed
desires; but it is surprising how nearly Buffon has approached the later
and truer theory, which may perhaps have been suggested to Dr. Darwin by
the following pregnant passage--as pregnant, probably, to Buffon himself
as to another:--

"The camel is the animal which seems to me to have felt the weight of
slavery most profoundly. He is born with wens upon his back and
callosities upon his knees and chest; these callosities are the
unmistakable results of rubbing, for they are full of pus and of
corrupted blood. The camel never walks without carrying a heavy burden,
and the pressure of this has hindered, for generations, the free
extension and uniform growth of the muscular parts of the back; whenever
he reposes or sleeps his driver compels him to do so upon his folded
legs, so that little by little this position becomes habitual with him.
All the weight of his body bears, during several hours of the day
continuously, upon his chest and knees, so that the skin of these parts,
pressed and rubbed against the earth, loses its hair, becomes bruised,
hardened, and disorganized.

"The llama, which like the camel passes its life beneath burdens, and
also reposes only by resting its weight upon its chest, has similar
callosities, which again are perpetuated in successive generations.
Baboons, and pouched monkeys, whose ordinary position is a sitting one,
whether waking or sleeping, have callosities under the region of the
haunches, and this hard skin has even become inseparable from the bone
against which it is being continually pressed by the weight of the body;
in the case, however, of these animals the callosities are dry and
healthy, for they do not come from the constraint of trammels, nor from
the burden of a foreign weight, but are the effects only of the natural
habits of the animal, which cause it to continue longer seated than in
any other position. There are callosities of these pouched monkeys which
resemble the double sole of skin which we have ourselves under our feet;
this sole is a natural hardness which our continued habit of walking or
standing upright will make thicker or thinner according to the greater
or less degree of friction to which we subject our feet."[122]

This involves the whole theory of Dr. Darwin.

Wild animals would not change either their food or climate if left to
themselves, and in this case they would not vary, bu