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