and of concealing themselves in the grass, their body,
owing to continually repeated efforts to elongate itself so as to
pass through narrow spaces, has acquired a considerable length
disproportionate to its size. Moreover, limbs would have been very
useless to these animals, and consequently would not have been
employed: because long legs would have interfered with their need of
gliding, and very short legs, not being more than four in number,
would have been incapable of moving their body. Hence the lack of
use of these parts having been constant in the races of these
animals, has caused the total disappearance of these same parts,
although really included in the plan of organization of the animals
of their class.

"Many insects which by the natural character of their order, and
even of their genus, should have wings, lack them more or less
completely from disuse. A quantity of Coleoptera, Orthoptera,
Hymenoptera, and of Hemiptera, etc., afford examples; the habits of
these animals do not require them to make use of their wings.

"But it is not sufficient to give the explanation of the cause which
has brought about the condition of the organs of different
animals--a condition which we see to be always the same in those of
the same species; we must besides observe the changes of condition
produced in the organs of one and the same individual during its
life, by the single result of a great change in the special habits
in the individuals of its species. The following fact, which is one
of the most remarkable, will serve to prove the influence of habits
on the condition of organs, and show how changes wrought in the
habits of an individual, produce the condition of the organs which
are brought into action during the exercise of these habits.

"M. Tenon, member of the Institute, has given an account to the
Class of Sciences, that having examined the intestinal canal of
several men who had been hard drinkers all their lives, he had
constantly found it to be shortened to an extraordinary extent,
compared with the same organ in those not given to such a habit.

"We know that hard drinkers, or those who are addicted to
drunkenness, take very little solid food, that they eat very
lightly, and that the beverage which they take in excess frequently
suffices to nourish them.

"Moreover, as fluid aliments, especially spirituous liquors, do not
remain