only as respiration, but as its products
digestion, strength, and, according to Cuvier, animal vitality vary. All
begin with respiration, end with it, and are as it is. If respiration
ceases, restore it before the organism is deranged, and they are all
restored. We must conclude, then, that respiration is the cause of
circulation, although we could not see how it should be. Much more, when
we discern a mighty power, that of expansion, and see how the Almighty
has made our frame in reference to its production by caloric--the lungs
allowing of heat within them like wet cloth, and the nerves, bones and
muscles all made and arranged, so that oxygen shall be brought to them
by respiration on the one hand, and carbon by the numerous digestive and
circulatory organs on the other.

As to any deficiency of power, my reviewer had omitted to notice that
not only the ordinary expansion of the water of the blood by calorie had
been assumed, but also its vaporization, or the change of such a portion
as was needed into steam, the lungs being _in vacuo_; so that nature
here had not failed of her usual abundance. And had not this power been
kept in check by the pressure of the surrounding air hindering the
perfect vacuum of the lungs, there was reason to fear, rather its excess
than its deficiency. As to the reviewer's assertion that heat is
generated in every part of the system, and imparted to the _solids_
equally with the fluids--that I positively denied, in the name of common
sense. For who does not know that, although there may be some heat
elaborated in the stomach, and some during the processes by which the
fluids change to solids, that the great source of heat to the system, is
in the fluid blood, and not in solid flesh or bone? Our senses of sight
and feeling show us, in the case of blushing, that heat comes and goes
with the blood. No one believes that the solid parts of his leg warm the
blood as much as it warms them. Finally, it discredited the old theory,
that it showed no adequate use for the great primary function of
respiration, and its constant attendant, animal heat. Breathing and
warmth are not ultimate ends. Man breathes to live; he does not live to
breathe. He is warm to live; he does not live merely to be warm. Our
theory shows that it is these primary agencies which sustain his being;
and it sets forth the manner in which they operate for this end. And
thus, while it indicates the wisdom of the Almighty in the for