224 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
of life, and variability ensues; but similar changes of conditions might 
and do occur under nature. Let it also be borne in mind how infinitely 
complex and close-fitting are the mutual relations of all organic beings 
to each other and to their physical conditions of life; and consequently 
what infinitely varied diversities of structure might be of use to 
each being under changing conditions of life. Can it, then, be 
thought improbable, seeing that variations useful to man have 
undoubtedly occurred, that other variations useful in some way to 
each being in the great and complex battle of life, should occur in 
the course of many successive generations? If such do occur, can 
we doubt (remembering that many more individuals are born than 
can possibly survive) that individuals having any advantage, however 
slight, over others, would have the best chance of surviving and of 
procreating their kind? On the other hand, we may feel sure that 
any variation in the least degree injurious would be rigidly destroyed. 
This preservation of favorable individual differences and variations, 
and the destruction of those which are injurious, I have called 
Natural Selection, or the Survival of the Fittest. Variations neither 
useful nor injurious would not be affected by natural selection, and 
would be left either a fluctuating element, as perhaps we see in certain 
polymorphic species, or would ultimately become fixed, owing to the 
nature of the organism and the nature of the conditions. 
Several writers have misapprehended or objected to the term 
Natural Selection. Some have even imagined that natural selection 
induces variability, whereas it implies only the preservation of such 
variations as arise and are beneficial to the being under its conditions 
of life. No one objects to agriculturists speaking of the potent effects 
of man’s selection; and in this case the individual differences given by 
nature, which man for some object selects, must of necessity first 
occur. Others have objected that the term selection implies conscious 
choice in the animals which become modified; and it has even been 
urged that, as plants have no volition, natural selection is not applic- 
able to them! In the literal sense of the word, no doubt, natural 
selection is a false term; but who ever objected to chemists speaking 
of the elective affinities of the various elements ?—and yet an acid 
cannot strictly be said to elect the base with which it in preference 
combines. It has been said that I speak of natural selection as an 
active power or Deity; but who objects to an author speaking of the 
attraction of gravity as ruling the movements of the planets? Every- 
one knows what is meant and is implied by such metaphorical expres- 
