t man knows nothing of the laws of
life and death. But what an answer to such presumption do the facts
rendered above supply. Life and death are here reduced, on given
conditions, to reasonings as clear and positive as are the reasonings
on the development of heat by the combustion of fuel. It is not
necessary for the vital philosopher to go out into the towns and
villages to take a new census of deaths to enable him to give us his
readings of the general mortality under the conditions specified. He
may sit in his cabinet, and, as he reads his thermometer day by day,
predict results. There is a fall of temperature that shall be known by
experience to be sufficiently deep and prolonged to cause an increase
of one death among those members of the community who have reached
thirty years. Then, rising by a definite rule, there have died
sixty-four, in proportion to that one, of those who have reached
eighty-four years. This is sound calculation, and it leads to
reflection. It leads one to ask, what, if the law be so definite, are
curative and preventive medicine doing meanwhile, that they shall not
disturb it? I fear that they hardly produce perturbations, and I do
not see why they should; because, as the truth opens itself to the
mind, the tremendous external change in the forces of the universe
that leads to the result, is not to be grappled with nor interfered
with by any specific method of human invention. The cause is too
general, too overwhelming, too grasping. It is like the lightning
stroke in its distance from our command; but it is widely spread, not
pointed and concentrate; prolonged, not instantaneous; and, by virtue
of these properties, is so much the more subtile and devastating.

At first it seems easy to explain the reason why a sudden fall in
temperature should lead to an increase in the number of deaths, and it
is to be admitted that, to a certain extent, the reason is clear.

ANIMAL POWER AT DIFFERENT PERIODS OF LIFE.

Without entering on the question whether heat is the animating
principle of all living organisms, we may accept that in the evolution
of heat in the body we have a measurement of the capacity of the body
to sustain motion, which is only another phrase for expressing the
resistance of the body to death. For example, if we assume that a
healthy man of thirty respires sufficient air per day to produce as
much heat as would raise fifty pounds of water at 32 deg. Fahr. to 212 deg.
Fahr., an