ism, for to this it must be
ascribed. To it energy is available which is denied to the
protozoon. Ingenious adaptations to environment are more
especially its privilege. A higher manifestation, however, was
possible, and was found in the development of mind. This, too, is
a servant of the cell, as the genii of the lamp. Through it
energy is available which is denied to the body. This is the
masterpiece of the cell. Its activity dates, as it were, but from
yesterday, and today it inherits the most diverse energies of the
Earth.

Taking this view of organic succession, we may liken the
individual to a particle vibrating for a moment and then coming
to rest, but sweeping out in its motion one wave in the
continuous organic vibration travelling from the past into the
future. But as this vibration is one spreading with increased
energy from each vibrating particle, its propagation involves a
continual accelerated inflow of energy from the surrounding
medium, a dynamic condition unknown in periodic effects
transmitted by inanimate actions, and, indeed, marking the
fundamental difference between the dynamic attitudes of the
animate and inanimate.

We can trace the periodic succession of individuals on a diagram
of activity with some advantage. Considering, first, the case of
the unicellular organism reproducing by subdivision and recalling
that conditions, definite and inevitable, oppose a limit to the
rate of growth, or, for our

86

present purpose, rate of consumption of energy, we proceed as
follows:

{Fig. 1}

Along a horizontal axis units of time are measured; along a
vertical axis units of energy. Then the life-history of the
amoeba, for example, appears as a line such as A in Fig. 1.
During the earlier stages of its growth the rate of absorption of
energy is small; so that in the unit interval of time, t, the
small quantity of energy, e1, is absorbed. As life advances, the
activity of the organism augments, till finally this rate attains
a maximum, when e2 units of energy are consumed in the unit of
time.[1]

[1] Reference to p. 76, where the organic system is treated as
purely mechanical, may help readers to understand what is
involved in this curve. The solar engine may, unquestionably,
have its activity defined by such a curve. The organism is,
indeed, more complex; but neither this fact nor our ignorance of
its mechanism, affects the principles which justify the diagram.

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On this diagram repro