It is reported that a French scientist has discovered the secret of the
glow-worm's light. Of course it is a chemical reaction,--what else could
it be?--but it is a chemical reaction in a vital process. Our mental and
spiritual life--our emotions of art, poetry, religion--are inseparable
from physical processes in the brain and the nervous system; but is
that their final explanation? The sunlight has little effect on a
withered leaf, but see what effect it has upon the green leaf upon the
tree! The sunlight is the same, but it falls upon a new force or potency
in the chlorophyll of the leaf,--a bit of chemistry there inspired by
life,--and the heat of the sun is stored up in the carbon or woody
tissues of the plant or tree, to be given out again in our stoves or
fireplaces. And behold how much more of the solar heat is stored up in
one kind of a tree than in certain other kinds,--how much in the
hickory, oak, maple, and how little comparatively in the pine, spruce,
linden,--all through the magic of something in the leaf, or shall we say
of the spirit of the tree? If the laws of matter and force alone account
for the living organism, if we do not have to think of something that
organizes, then how do we account for the marvelous diversity of living
forms, and their still more marvelous power of adaptation to changed
conditions, since the laws of matter and force are the same everywhere?
Science can deal only with the mechanism and chemistry of life, not with
its essence; that which sets up the new activity in matter that we call
vital is beyond its analysis. It is hard to believe that we have told
the whole truth about a living body when we have enumerated all its
chemical and mechanical activities. It is by such enumeration that we
describe a watch, or a steam-engine, or any other piece of machinery.
Describe I say, but such description does not account for the watch or
tell us its full significance. To do this, we must include the
watchmaker, and the world of mind and ideas amid which he lives. Now, in
a living machine, the machine and the maker are one. The watch is
perpetually self-wound and self-regulated and self-repaired. It is made
up of millions of other little watches, the cells, all working together
for one common end and ticking out the seconds and minutes of life with
unfailing regularity. Unlike the watch we carry in our pockets, if we
take it apart so as to stop its ticking, it can never be put together
again. It has not merely stopped; it is dead.
The late William Keith Brooks, of Johns Hopkins University, said in
opposition to Huxley that he held to the "old-fashioned conviction that
living things do in some way, and in some degree, control or condition
inorganic nature; that they hold their own by setting the mechanical
properties of matter in opposition to each other, and that this is their
most notable and distinctive characteristic." And yet, he said, to think
of the living world as "anything but natural" is impossible.