a 56 lb.
weight, and by the contraction of my biceps lift it through the
vertical space of a foot. The blood and tissue consumed during this
contraction have not developed in the muscle their due amount of heat.
A quantity of heat is at this moment missing in my muscle which would
raise the temperature of an ounce of water somewhat more than one
degree Fahrenheit. I liberate the weight: it falls to the earth, and
by its collision generates the precise amount of heat missing in the
muscle. My muscular heat is thus transferred from its local hearth to
external space. The fuel is consumed in my body, but the heat of
combustion is produced outside my body. The case is substantially the
same as that of the Voltaic battery when it performs external work, or
produces external heat. All this points to the conclusion that the
force we employ in muscular exertion is the force of burning fuel and
not of creative will. In the light of these facts the body is seen to
be as incapable of generating energy without expenditure, as the
solids and liquids of the Voltaic battery. The body, in other words,
falls into the catagory of machines.

We can do with the body all that we have already done with the
battery--heat platinum wires, decompose water, magnetise iron, and
deflect a magnetic needle. The combustion of muscle may be made to
produce all these effects, as the combustion of zinc may be caused to
produce them. By turning the handle of a magneto-electric machine a
coil of wire may be caused to rotate between the poles of a magnet. As
long as the two ends of the coil are unconnected we have simply to
overcome the ordinary inertia and friction of the machine in turning
the handle. But the moment the two ends of the coil are united by a
thin platinum wire a sudden addition of labour is thrown upon the
turning arm. When the necessary labour is expended, its equivalent
immediately appears. The platinum wire glows. You can readily
maintain it at a white heat, or even fuse it. This is a very
remarkable result. From the muscles of the arm, with a temperature of
100 degrees, we extract the temperature of molten platinum, which is
nearly four thousand degrees. The miracle here is the reverse of that
of the burning bush mentioned in Exodus. There the bush burned, but
was not consumed--here the body is consumed, but does not burn. The
similarity of the action with that of the Voltaic battery when it
heats an external wire i