of spirit; but does it bring us any
nearer the origin of life? Is radio-active matter any nearer living
matter than is the clod under foot? Are the darting electrons any more
vital than the shooting-stars? Can a flash of radium emanations on a
zinc-sulphide plate kindle the precious spark? It is probably just as
possible to evoke vitality out of the clash of billiard-balls as out of
the clash of atoms and electrons. This allusion to billiard-balls
recalls to my mind a striking passage from Tyndall's famous Belfast
Address which he puts in the mouth of Bishop Butler in his imaginary
argument with Lucretius, and which shows how thoroughly Tyndall
appreciated the difficulties of his own position in advocating the
theory of the physico-chemical origin of life.

The atomic and electronic theory of matter admits one to a world that
does indeed seem unreal and fantastic. "If my bark sinks," says the
poet, "'t is to another sea." If the mind breaks through what we call
gross matter, and explores its interior, it finds itself indeed in a
vast under or hidden world--a world almost as much a creation of the
imagination as that visited by Alice in Wonderland, except that the
existence of this world is capable of demonstration. It is a world of
the infinitely little which science interprets in terms of the
infinitely large. Sir Oliver Lodge sees the molecular spaces that
separate the particles of any material body relatively like the
interstellar spaces that separate the heavenly bodies. Just as all the
so-called solid matter revealed by our astronomy is almost infinitesimal
compared with the space through which it is distributed, so the
electrons which compose the matter with which we deal are comparable to
the bodies of the solar system moving in vast spaces. It is indeed a
fantastic world where science conceives of bodies a thousand times
smaller than the hydrogen atom--the smallest body known to science;
where it conceives of vibrations in the ether millions of millions times
a second; where we are bombarded by a shower of corpuscles from a
burning candle, or a gas-jet, or a red-hot iron surface, moving at the
speed of one hundred thousand miles a second! But this almost omnipotent
ether has, after all, some of the limitations of the finite. It takes
time to transmit the waves of light from the sun and the stars. This
measurable speed, says Sir Oliver Lodge, gives the ether away, and shows
its finite character.

It seems as if