it them for giving
perfection to the senses of smell, sight, and hearing, so necessary to
animals of prey. In short, the shape and structure of the teeth regulate
the forms of the condyle, of the shoulder-blade, and of the claws,
in the same manner as the equation of a curve regulates all its other
properties; and as in regard to any particular curve all its properties
may be ascertained by assuming each separate property as the foundation
of a particular equation, in the same manner a claw, a shoulder-blade,
a condyle, a leg or arm bone, or any other bone separately considered,
enables us to discover the description of teeth to which they have
belonged; and so also reciprocally we may determine the forms of the
other bones from the teeth. Thus commencing our investigations by a
careful survey of any one bone by itself, a person who is sufficiently
master of the laws of organic structure may, as it were, reconstruct the
whole animal to which that bone belonged."(1)

We have already pointed out that no one is quite able to perform the
necromantic feat suggested in the last sentence; but the exaggeration is
pardonable in the enthusiast to whom the principle meant so much and in
whose hands it extended so far.

Of course this entire principle, in its broad outlines, is something
with which every student of anatomy had been familiar from the time
when anatomy was first studied, but the full expression of the "law
of co-ordination," as Cuvier called it, had never been explicitly made
before; and, notwithstanding its seeming obviousness, the exposition
which Cuvier made of it in the introduction to his classical work on
comparative anatomy, which was published during the first decade of
the nineteenth century, ranks as a great discovery. It is one of those
generalizations which serve as guideposts to other discoveries.

BICHAT AND THE BODILY TISSUES

Much the same thing may be said of another generalization regarding the
animal body, which the brilliant young French physician Marie Francois
Bichat made in calling attention to the fact that each vertebrate
organism, including man, has really two quite different sets of
organs--one set under volitional control, and serving the end of
locomotion, the other removed from volitional control, and serving the
ends of the "vital processes" of digestion, assimilation, and the like.
He called these sets of organs the animal system and the organic system,
respectively. The division