Selection is not a thing once done and then dropped—natural selection is continuous and never-ending, except in rare and special circumstances, such as man may bring about by his interference, and then it does not really cease but only changes its demand. The characteristics of a race or species are maintained by natural selection, just as much as they are produced by it. Cessation of a previously active selection (which is sometimes brought about by exceptional conditions) results in a departure of the individuals of the race, no longer subject to that selection, from the standard of form and characteristics previously maintained. To understand this, we must consider for a moment the great property of living things, which is called “variation.”

No two animals, or plants even, when born of the same parents, are ever exactly alike. Not only that, but if we look at a great number of individuals of a race or stock, we find that some are very different from the others, in colour, in proportion of parts, in character, and other qualities. As a rule it is difficult to look at such a number, because in Nature only two on the average out of many hundreds, sometimes thousands, born from a single pair of parents, grow up to take their parents’ place, and these two are those “selected” by natural survival on account of their close resemblance to the parents. But if we experimentally rear all the offspring of a plant or animal to full growth—not allowing them to perish by competition for food, or place, or by inability to escape enemies—then we see more clearly how great is the in-born variation, how many and wide are the departures from the favoured standard form which are naturally born and owe their peculiarities to this birth-quality—called innate or congenital variation—and not to anything which happens to them afterwards differing from what happens to their brothers and sisters.

Of course, we are all familiar with this “congenital or innate variation,” as shown by brothers and sisters in human families. How and why do innate variations arise? They arise from chemical and mechanical action upon the “germs” or reproductive cells contained in the body of the parents, and also sometimes from the mating in reproduction of two strains or races which are already different from one another. When an animal or plant is given unaccustomed food or brought up in new surroundings (as, for instance, in captivity) its germs are affected, and they produce variations in the next generation more abundantly. The best analogy for what occurs is that of a “shaking up” or disturbance of the particles of the germ or reproductive material, somewhat as the beads and bits of glass in a kaleidoscope are shaken and change from one well-balanced arrangement to another. And the same analogy applies to the crossing or fertilising of “strain” or “race” by another differing from it. A disturbance is the consequence, and a departure in the form and character of the young from anything arrived at before often takes place. These variations have no necessary fitness or correspondence to the changed conditions which have produced them. They are, so to speak, departures in all and every direction—not very great, but still great enough to be selected by survival if occurring in wild extra-human nature, and obvious enough when produced in cultivated animals and plants to be seen and selected by man, the stock-breeder or fancier.

Indeed the stock-breeder and horticulturist go to work in this way deliberately. Though when they have fattened an animal or fed up a plant they cannot make it transmit its fatness or increased size to its offspring, yet they can, by special feeding and change of conditions of life—or by cross-breeding—break up the fixed tendency or quality of the germs within the parents so treated. Thus they get offspring produced which show strange and unexpected variations of many kinds—new feathers, new colours, new shapes of leaf, increased size of root, length of limb—all kinds of variations. From the congenital varieties thus produced by “stirring up,” “breaking down,” or disturbing the germ-matter (germ-plasm) of the parents, the breeder next proceeds to select and mate those which show the character which suits his fancy, whilst he destroys or rejects the others. Thus he establishes, and by repeated selection in every generation maintains, and if he desires increases, the characteristics which he values.

Birth-variation is then an inherent property of living things (including man) as much as heredity, which is the name for the property expressed in the resemblance of offspring to parent. And birth-variation, or congenital variation—that is to say, the being born with a power to grow into something different (not greatly, but still obviously, different) from their parents or ancestry, and from their brethren and cousins, though not subjected after birth to any treatment or conditions differing from those common to all of them—is a quality of living things which must be distinguished altogether from the power of the individual itself, though not born with qualities differing from those of its brothers and sisters, to vary or change in some respects as compared with other individuals when it is specially fed or exposed to special treatment. The first is change, or variation, of the “stirps,” or germ plasm; the second is change, or variation, of the transient body of the individual. The first is indefinite and may be of almost any kind or form; once it has appeared, it is a permanent possession of the race descended from its owner. The second is definite and a direct reaction to the environment. Such an individually induced or stimulated change is often called an “acquired character.” It does not affect the stirps, the inner reproductive germs, and cannot be handed on by inheritance to a new generation.

What happens, then, when there is a cessation of selection? All sorts of birth-variations appear and grow up. The fine adjustment of form—maintained by natural selection carried on unceasingly—no longer obtains. The characteristics of the race become less emphasised. All sorts of birth-variations have an equal chance, and the tendency must be for those characteristics which have most recently been established and maintained by severe selection to dwindle and then to disappear altogether. The majority of birth-variations will—when selection is prevented—always tend to present a lessened, rather than an increased, development of any one characteristic—the excelling minority will no longer be selected, but all will have an equal chance in mating and reproducing. Hence, bit by bit, all salient features, all the characteristics of the race previously maintained by selection, will, as a result of survival of all variations and general crossing and interbreeding—dwindle and disappear. It is to this process that the term “degeneration” has been applied by biologists. How far it may go, and what are its limits and various outcomes, I cannot now discuss. It is sometimes spoken of as “retrogression”—which implies wrongly a return to a previous state. From some points of view it might be called “simplification.”

The point to which I have been making is this—that civilised mankind appears to be very nearly in regard to most points of structure and quality in a condition of “cessation of selection.” It is the better-provided and well-fed, well-clothed, protected classes of the community, in which this cessation of selection is most complete. Racial degeneration is, therefore, to be looked for in those classes quite as much as in the half-starved, ill-clad, struggling poor, if, indeed, it should not be expected to be more strongly marked in them. There are facts which tend to show that such anticipations are well-founded.

This is a matter requiring further discussion. It is probable, I may say in anticipation, that whilst natural selection in the struggle for existence is only obscurely operative (except as to alcoholism and some diseases) in civilised man, yet what Mr. Darwin called sexual selection—the influence of preference in mating—has an important scope, and it may be that hereafter it will be of enormous importance in maintaining the quality of the race.

Meanwhile, it seems that the unregulated increase of the population, the indiscriminate, unquestioning protection of infant life and of adult life also—without selection or limitation—must lead to results which can only be described as general degeneration. How far such a conclusion is justified, and what are possible modifying or counteracting influences at work which may affect the future of mankind, are questions of surpassing interest. In any case, it is interesting to note that the cessation of selection is more complete, and the consequent degeneration of the race would, therefore, seem to be more probable in the higher propertied classes than in the bare-footed toilers, whose ranks are thinned by starvation and early death. One may well ask, “Is this really so?”