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the duration of the individual is, indeed, very probably revealed
in the fact that short-lived animals most generally reproduce
themselves rapidly and in great abundance, and vice versa. In
many cases where this appears contradicted, it will be found that
the young are exposed to such dangers that but few survive (_e.g._
many of the reptilia, etc.), and so the rate of reproduction is
actually slow.
Death through the periodic rigour of the inanimate environment
calls forth phenomena very different from death introduced or
favoured by competition. A multiplicity of effects simulative of
death occur. Organisms will, for example, learn to meet very
rigorous conditions if slowly introduced, and not permanent. A
transitory period of want can be tided over by contrivance. The
lily withdrawing its vital forces into the bulb, protected from
the greatest extremity of rigour by seclusion in the Earth; the
trance of the hibernating animal; are instances of such
contrivances.
But there are organisms whose life-wave truly takes up the
periodicity of the Earth in its orbit. Thus the smaller animals
and plants, possessing less resources in themselves, die at the
approach of winter, propagating themselves by units which,
whether egg or seed, undergo a period of quiescence during the
season of want. In these quiescent units the energy of the
organism is potential, and the time-energy function is in
abeyance. This condition is, perhaps, foreshadowed in the
encyst-
94
ment of the amoeba in resistance to drought. In most cases of
hibernation the time-energy function seems maintained at a loss
of potential by the organism, a diminished vital consumption of
energy being carried on at the expense of the stored energy of
the tissues. So, too, even among the largest organisms there will
be a diminution of activity periodically inspired by
climatological conditions. Thus, wholly or in part, the activity
of organisms is recurrently affected by the great energy--tides
set up by the Earth's orbital motion.
{Fig. 6}
Similarly in the phenomenon of sleep the organism responds to the
Earth's axial periodicity, for in the interval of night a period
of impoverishment has to be endured. Thus the diurnal waves of
energy also meet a response in the organism. These tides and
waves of activity would appear as larger and smaller ripples
95
on the life-curve of the organism. But in some, in which life and
death are encompassed in a day, this would not be so; and for the
annual among plants, the seed rest divides the waves with lines
of no activity (Fig. 6).
Thus, finally, we regard the organism as a dynamic phenomenon
passing through periodic variations of intensity. The material
systems concerned in the transfer of the energy rise, flourish,
and fall in endless succession, like cities of ancient dynasties.
At points of similar phase upon the waves the rate of consumption
of energy is approximately the same; the functions, too, which
demand and expend the energy are of similar nature.
That the rhythm of these events is ultimately based on harmony in
the configuration and motion of the molecules within the germ
seems an unavoidable conclusion. In the life of the individual
rhythmic dynamic phenomena reappear which in some cases have no
longer a parallel in the external world, or under conditions when
the individual is no longer influenced by these external
conditions.,, In many cases the periodic phenomena ultimately die
out under new influences, like the oscillations of a body in a
viscous medium; in others when they seem to be more deeply rooted
in physiological conditions they persist.