alists, on the other hand, have believed that species undergo
modification, and that the existing forms of life are the descendants
by true generation of pre existing forms. Passing over allusions to
the subject in the classical writers (Aristotle, in his "Physicae
Auscultationes" (lib.2, cap.8, s.2), after remarking that rain does not
fall in order to make the corn grow, any more than it falls to spoil the
farmer's corn when threshed out of doors, applies the same argument
to organisation; and adds (as translated by Mr. Clair Grece, who first
pointed out the passage to me), "So what hinders the different parts (of
the body) from having this merely accidental relation in nature? as the
teeth, for example, grow by necessity, the front ones sharp, adapted
for dividing, and the grinders flat, and serviceable for masticating
the food; since they were not made for the sake of this, but it was the
result of accident. And in like manner as to other parts in which there
appears to exist an adaptation to an end. Wheresoever, therefore, all
things together (that is all the parts of one whole) happened like as if
they were made for the sake of something, these were preserved,
having been appropriately constituted by an internal spontaneity; and
whatsoever things were not thus constituted, perished and still perish."
We here see the principle of natural selection shadowed forth, but
how little Aristotle fully comprehended the principle, is shown by his
remarks on the formation of the teeth.), the first author who in modern
times has treated it in a scientific spirit was Buffon. But as his
opinions fluctuated greatly at different periods, and as he does not
enter on the causes or means of the transformation of species, I need
not here enter on details.

Lamarck was the first man whose conclusions on the subject excited much
attention. This justly celebrated naturalist first published his views
in 1801; he much enlarged them in 1809 in his "Philosophie Zoologique",
and subsequently, 1815, in the Introduction to his "Hist. Nat. des
Animaux sans Vertebres". In these works he up holds the doctrine that
all species, including man, are descended from other species. He first
did the eminent service of arousing attention to the probability of
all change in the organic, as well as in the inorganic world, being the
result of law, and not of miraculous interposition. Lamarck seems
to have been chiefly led to his conclusion on the gradual change