We find in the human being three principles, _different, and yet in
complete union_: 1. The body; 2. The vital energy; 3. The soul. I
name them thus in order that I may follow the _a posteriori_ method.
The body is an association of molecules which are themselves formed
of groups of atoms. The atoms are inert, passive, immutable, and
indestructible. They enter into the organism by means of respiration
and alimentation; they renew the tissues incessantly, and are
continually replaced by others, and when cast out from the body go to
form other bodies. In a few months the human body is entirely renewed,
and neither in the blood, nor in the flesh, nor in the brain, nor in
the bones, does an atom remain of those which constituted the body
a few months before. The atoms travel without ceasing from body to
body, chiefly by the grand medium of the atmosphere. The molecule of
iron is the same whether it be incorporated in the blood which throbs
in the temples of an illustrious man, or form part of a fragment of
rusty iron; the molecule of oxygen is the same in the blush raised by
a loving glance, or when in union with hydrogen it forms the flame of
one of the thousand jets of gas that illuminate Paris by night, or when
it falls from the clouds in the shape of a drop of water. The bodies
of the living are formed of the ashes of the dead, and if all the dead
were to be resuscitated, the last comers might find the material for
their bodies wanting, owing to their predecessors having appropriated
all that was available. Moreover, during life many exchanges are made
between enemies and friends, between men, animals, and plants, which
amaze the analyst who looks at them with the eyes of science. That
which you breathe, eat, and drink, has been breathed, drunk, and eaten
millions of times before. Such is the human body, an assemblage of
molecules of matter which are constantly being renewed. The principle
by which these molecules are grouped according to a certain form so as
to produce an organism, is the vital energy of life. The inert, passive
atoms, incapable of guiding themselves, are ruled by vital force, which
calls them, makes them come, takes hold of them, places and disposes of
them according to certain laws, and forms this marvellously-organised
body, which the anatomist and the physiologist contemplate with wonder.
[Sidenote: Atoms indestructible.]
[Sidenote: Vital energy or force in nature and man.]
[Sidenote: Vital force has limits.]