and clearly, where motion is, stasis is not. Sooner or later, in its
ceaseless flight through space, the dark star must collide with some
other stellar body, as Dr. Croll imagines of the dark bodies which his
"pre-nebular theory" postulates. Such collision may be long delayed; the
dark star may be drawn in comet-like circuit about thousands of other
stellar masses, and be hurtled on thousands of diverse parabolic or
elliptical orbits, before it chances to collide--but that matters not:
"billions are the units in the arithmetic of eternity," and sooner
or later, we can hardly doubt, a collision must occur. Then without
question the mutual impact must shatter both colliding bodies into
vapor, or vapor combined with meteoric fragments; in short, into a
veritable nebula, the matrix of future worlds. Thus the dark star, which
is the last term of one series of cosmic changes, becomes the first term
of another series--at once a post-nebular and a pre-nebular condition;
and the nebular hypothesis, thus amplified, ceases to be a mere linear
scale, and is rounded out to connote an unending series of cosmic
cycles, more nearly satisfying the imagination.

In this extended view, nebulae and luminous stars are but the infantile
and adolescent stages of the life history of the cosmic individual; the
dark star, its adult stage, or time of true virility. Or we may think of
the shrunken dark star as the germ-cell, the pollen-grain, of the cosmic
organism. Reduced in size, as becomes a germ-cell, to a mere fraction
of the nebular body from which it sprang, it yet retains within
its seemingly non-vital body all the potentialities of the original
organism, and requires only to blend with a fellow-cell to bring a new
generation into being. Thus may the cosmic race, whose aggregate census
makes up the stellar universe, be perpetuated--individual solar systems,
such as ours, being born, and growing old, and dying to live again in
their descendants, while the universe as a whole maintains its unified
integrity throughout all these internal mutations--passing on, it may
be, by infinitesimal stages, to a culmination hopelessly beyond human
comprehension.

III. THE NEW SCIENCE OF PALEONTOLOGY

WILLIAM SMITH AND FOSSIL SHELLS

Ever since Leonardo da Vinci first recognized the true character of
fossils, there had been here and there a man who realized that the
earth's rocky crust is one gigantic mausoleum. Here and there a
dilettante ha