Now to survive is to survive to breed. If you live to eighty, and have no children, you do not survive in the biological sense; whereas your neighbour who died at forty may survive in a numerous progeny. Natural selection is always in the last resort between individuals; because individuals are alone competent to breed. At the same time, the reason for the individual's survival may lie very largely outside him. Amongst the bees, for instance, a non-working type of insect survives to breed because the sterile workers do their duty by the hive. So, too, that other social animal, man, carries on the race by means of some whom others die childless in order to preserve. Nevertheless, breeding being a strictly individual and personal affair, there is always a risk lest a society, through spending its best too freely, end by recruiting its numbers from those in whom the engrained capacity to render social service is weakly developed. To rear a goodly family must always be the first duty of unselfish people; for otherwise the spirit of unselfishness can hardly be kept alive the world. Enough about heredity as a condition of evolution. We return, with a better chance of distinguishing them, to the consideration of the special effects that it brings about. It was said just now that heredity is the stiffening in human nature, a stiffening bound up with a more or less considerable offset of plasticity. Now clearly it is in some sense true that the child's whole nature, its modicum of plasticity included, is handed on from its parents. Our business in this chapter, however, is on the whole to put out of our thoughts this plastic side of the inherited life-force. The more or less rigid, definite, systematized characters--these form the hereditary factor, the race. Now none of these are ever quite fixed. A certain measure of plasticity has to be counted in as part of their very nature. Even in the bee, with its highly definite instincts, there is a certain flexibility bound up with each of these; so that, for instance, the inborn faculty of building up the comb regularly is modified if the hive happens to be of an awkward shape. Yet, as compared with what remains over, the characters that we are able to distinguish as racial must show fixity. Unfortunately, habits show fixity too. Yet habits belong to the plastic side of our nature; for, in forming a habit, we are plastic at the start, though hardly so once we have let ourselves go. Habits, then, must be discounted in our search for the hereditary bias in our lives. It is no use trying to disguise the difficulties attending an inquiry into race. * * * * *