d its faculties are no
longer the same. The second become clumsy; they are unable to fly,
and grow more fleshy in all parts of their bodies.

"Behold in our stout and clumsy horses, habituated to draw heavy
loads, and which constitute a special race by always being kept
together--behold, I say, the difference in their form compared with
those of English horses, which are all slender, with long necks,
because for a long period they have been trained to run swiftly:
behold in them the influence of a difference of habit, and judge for
yourselves. You find them, then, such as they are in some degree in
nature. You find there our cock and our hen in the condition we have
[made] them, as also the mixed races that we have formed by mixed
breeding between the varieties produced in different countries, or
where they were so in the state of domesticity. You find there
likewise our different races of domestic pigeons, our different
dogs, etc. What are our cultivated fruits, our wheat, our cabbage,
our lettuce, etc., etc., if they are not the result of changes which
we ourselves have effected in these plants, in changing by our
culture the conditions of their situation? Are they now found in
this condition in nature? To these incontestable facts add the
considerations which I have discussed in my _Recherches sur les
Corps vivans_ (p. 56 _et suiv._), and decide for yourselves.

"Thus, among living bodies, nature, as I have already said, offers
only in an absolute way individuals which succeed each other
genetically, and which descend one from the other. So the _species_
among them are only relative, and only temporary.

"Nevertheless, to facilitate the study and the knowledge of so many
different bodies it is useful to give the name of _species_ to the
entire collection of individuals which are alike, which reproduction
perpetuates in the same condition as long as the conditions of their
situation do not change enough to make their habits, their
character, and their form vary.

"Such is, citizens, the exact sketch of that which goes on in nature
since she has existed, and of that which the observation of her acts
has alone enabled us to discover. I have fulfilled my object if, in
presenting to you the results of my researches and of my experience,
I have been able to disclose to you that which in your studies of
this kind deserves your special attention.