even a large portion of the skeleton of an extinct animal, and
yet be unable to reconstruct its skull or its limbs. It is only
when the tooth or bone presents peculiarities, which we know by
previous experience to be characteristic of a certain group,
that we can safely predict that the fossil belonged to an animal
of the same group. Any one who finds a cow's grinder may be
perfectly sure that it belonged to an animal which had two
complete toes on each foot and ruminated; any one who finds a
horse's grinder may be as sure that it had one complete toe on
each foot and did not ruminate; but if ruminants and horses were
extinct animals of which nothing but the grinders had ever been
discovered, no amount of physiological reasoning could have
enabled us to reconstruct either animal, still less to have
divined the wide differences between the two. Cuvier, in the
"Discours sur les Revolutions de la Surface du Globe," strangely
credits himself, and has ever since been credited by others,
with the invention of a new method of palaeontological research.
But if you will turn to the "Recherches sur les Ossemens
Fossiles" and watch Cuvier, not speculating, but working, you
will find that his method is neither more nor less than that of
Steno. If he was able to make his famous prophecy from the jaw
which lay upon the surface of a block of stone to the pelvis of
the same animal which lay hidden in it, it was not because
either he, or any one else, knew, or knows, why a certain form
of jaw is, as a rule, constantly accompanied by the presence of
marsupial bones, but simply because experience has shown that
these two structures are co-ordinated.


The settlement of the nature of fossils led at once to the next