112
ence was acquired far back in the evolutionary history of the
flower.[1]
But a further consideration arises. Not only at each moment in
the life of the individual must maximum income and most judicious
expenditure be considered, but in its whole life history, and
even over the history of its race, the efficiency must tend to be
a maximum. This principle is even carried so far that when
necessary it leads to the death of the individual, as in the case
of those organisms which, having accomplished the reproductive
act, almost immediately expire. This view of nature may be
repellent, but it is, nevertheless, evident that we are parts of
a system which ruthlessly sacrifices the individual on general
grounds of economy. Thus, if the curve which defines the mean
rate of reception of energy of all kinds at different periods in
the life of the organism be opposed by a second curve, drawn
below the axis along which time is measured, representing the
mean rate of expenditure of energy on development, reproduction,
etc. (Fig. 7), this latter curve, which is, of course,
[1] The blooms of self-fertilising, and especially of
cleistogamic plants (_e.g._ Viola), are examples of unconscious
memory, or unconscious "association of ideas" leading to the
development of organs now functionless. The _Pontederia crassipes_
of the Amazon, which develops its floating bladders when grown in
water, but aborts them rapidly when grown on land, and seems to
retain this power of adaptation to the environment for an
indefinite period of time, must act in each case upon an
unconscious memory based upon past experience. Many other cases
might be cited.
113
physiologically dependent on the former, must be of such a nature
from its origin to its completion in death, that the condition is
realized of the most economical rate of expenditure at each
period of life.[1] The rate of expenditure of energy at any
period of life is, of course, in such a curve defined by the
slope of the curve towards the axis of time at the period in
question; but this particular slope _must be led to by a previous
part of the curve, and involves its past and future course to a
very great extent_.
{Fig. 7}
There will, therefore, be impressed upon the
organism by the factors of evolution a unified course of
economical expenditure completed only by its death, and which
will give to the developmental progress of the individual its
prophetic character.
In this way we look to the unified career of each organic unit,
from its commencement in the ovum to the day
[1] See _The Abundance of Life_.