nt term "vital force."
Modern science shies at the term "force." We must have force or energy
or pressure of some kind to lift dead matter up into the myriad forms of
life, though in the last analysis of it it may all date from the sun.
When it builds a living body, we call it a vital force; when it builds a
gravel-bank, or moves a glacier, we call it a mechanical force; when it
writes a poem or composes a symphony, we call it a psychic force--all
distinctions which we cannot well dispense with, though of the ultimate
reality for which these terms stand we can know little. In the latest
science heat and light are not substances, though electricity is. They
are peculiar motions in matter which give rise to sensations in certain
living bodies that we name light and heat, as another peculiar motion in
matter gives rise to a sensation we call sound. Life is another kind of
motion in certain aggregates of matter--more mysterious or inexplicable
than all others because it cannot be described in terms of the others,
and because it defies the art and science of man to reproduce.

Though the concepts "vital force" and "life principle" have no standing
in the court of modern biological science, it is interesting to observe
how often recourse is had by biological writers to terms that embody
the same idea. Thus the German physiologist Verworn, the determined
enemy of the old conception of life, in his great work on
"Irritability," has recourse to "the specific energy of living
substances." One is forced to believe that without this "specific
energy" his "living substances" would never have arisen out of the
non-living.

Professor Moore, of Liverpool University, as I have already pointed out
while discussing the term "vital force," invents a new phrase, "biotic
energy," to explain the same phenomena. Surely a force by any other name
is no more and no less potent. Both Verworn and Moore feel the need, as
we all do, of some term, or terms, by which to explain that activity in
matter which we call vital. Other writers have referred to "a peculiar
power of synthesis" in plants and animals, which the inanimate forms do
not possess.

Ray Lankester, to whom I have already referred in discussing this
subject, helps himself out by inventing, not a new force, but a new
substance in which he fancies "resides the peculiar property of living
matter." He calls this hypothetical substance "plasmogen," and thinks of
it as an ultimate chemical c