Part 9
The only way in which a quality, good or bad, desirable or undesirable, is intensified, made inherent and dominant in a race or strain or family, is by selective breeding--selection due to natural rejection of those individuals not possessing the quality, or to artificial rejection of such individuals by the stock owner and breeder. No human maker of breeds--whether of cattle, horses, birds, or plants--ever yet proceeded by exercising, feeding, educating, or otherwise manipulating his sires and dams; he simply selects those as parents which by natural variation have the quality, more or less, which he desires, and he destroys or sterilises those which fail to satisfy his requirements. He is perfectly confident that in this way he can ensure the reproduction and exaggeration or dominance of the characteristics which he desires; he knows that he cannot obtain a “strain” or “breed” by any treatment, any feeding, or education of those which are born without the natural, innate possession of the desired quality, in a more or less marked degree. Once the characteristic turns up as a congenital variation, it can be intensified by coupling its possessor with a mate of like quality; but both sire and dam have to be rigidly selected with this purpose in view. Such methods are not adopted in human families, even royal ones.
In considering these questions as to characteristic qualities or want of qualities in groups and classes of human communities, we see then that we have in the first instance to distinguish very broadly between the body or structure of the individual, and the “stirps” or germ of the race which he carries within him. The former may be vastly changed for the better or worse as compared with average individuals, without affecting in any way the latter. The germ is carried by the individual member of the race in an almost complete state of isolation or safety from the influences which affect the individual’s structure generally (his body as distinct from his germinal or reproductive substance) injuriously or beneficially. The germ varies also, but independently. That is a matter of primary importance. Equally important in the case of man is a peculiarity which affects his manifestation of qualities in a way unknown in any other living thing.
Human society, in more marked and dominating form, in proportion as it is what we call “civilised,” has created for itself an inheritance which is not dependent on the variations of strains and the laws of actual breeding. Over and above--very much above--what each man inherits in the form of qualities and characteristics of his special family and stock--is the enormous mass of accumulated experience, knowledge, tradition, custom, and law--which pervades and envelops, as it were, the mere physical generations of this or that pullulating crowd of human individuals. Tradition, at first conveyed by gesture and imitativeness from parents to offspring, then by word of mouth, then by writing, and finally by printed record, sanctioned and enforced by all kinds of persuasion and compulsion--has culminated in an educative discipline which affects every individual in the community in the most powerful way--and constitutes an inheritance of a significance and activity altogether transcending, and independent of that due to the physical transmission of bodily and mental qualities. Public opinion, law, knowledge, belief, custom, and habit exist, and pursue their own course of change, as it were, outside the successive bodily generations of a population. Yet they determine in very large measure the characteristics which each class, and the community as a whole, exhibit. We have to distinguish those results which are due to physical heredity, similar in man and in animals--from results due to this all-powerful education peculiar to man--education, which for civilised man proceeds from almost innumerable sources--from parents, nurses, playfellows, companions, social, professional, and political organisations, as well as from the professed teacher, and from the local peculiarities of the simplest conditions of life. Hence it is that man inherits very little in the way of ready-made instincts, tricks of his nervous mechanism--but, on the contrary, has an enormously long period of individual growth and education, and inherits “educability” to a degree which varies in every family and race.
To estimate correctly, and so to deal with these various factors in human life, we require to know in detail the laws of breeding, heredity, variation, and selection in animals, and, further, the laws or formulated results of enquiry as to the “educability” of the human being, the range and the limits of “education,” the relation of hereditary quality to education, the causes of mental aberration and defect, of mental qualities of all kinds, the value and the dangers of all kinds of educational influences, whether physical, social, or intellectual. These are matters in regard to which there must be in the future more and more of common knowledge and agreement; at present they are lightly touched by politicians and journalists in a way which is inconsistent with a knowledge of the facts or of their importance.
When publicists airily declare that the virtues of kings and the vices of paupers are both due to the hereditary transmission of characters acquired by the peculiarities of diet and exercise of the progenitors of these classes it is time to protest. To cite the name of Darwin and “the laws which govern animal and plant life,” in support instead of in condemnation of such baseless fancies, is, one must suppose, an evidence, not of a desire to mislead, but of a regrettable indifference to the conclusions of that branch of human knowledge which is of more importance than any other to the statesman and the philanthropist.
“Selection,” whether due to survival in the struggle for existence or exercised by man as a “breeder” or “fancier,” is the only way in which new characteristics, good or bad, can be implanted in a race or stock, and become part of the hereditary quality of that race or stock. This applies equally to man and to animals and plants. And this selection is no temporary or casual thing. It means “the selection for breeding” of those individuals which spontaneously by the innate variability which all living things show (so that no two individuals are exactly alike) have exhibited from birth onwards, more or less clearly, indications of the characteristic which is to be selected. Nothing done to them after birth, and not done to others of their family or race, causes the desired characteristic; it appears unexpectedly, almost unaccountably as an in-born quality. It may be a slight difference only, not easy to take note of; but if it enables those who possess it to get the better of their competitors in the struggle for life, they will survive and mate and so transmit their characteristic to the next generation, whilst those who do not possess it and are beaten in life and fail to obtain food, safety, and mates, will perish and disappear, and their defective strain will perish with them.
37. _Variation and Selection Among Living Things_
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?”
38. _The Movement, Growth, and Dwindling of Glaciers_
Last summer we were watching the gradual change of the brilliant sunlight on the snows of Mont Blanc as the shadows crept up the pine-covered sides of the valley of Chamonix. We noted how the highest peak--the true summit of Mont Blanc--remained almost white and brilliant when the somewhat lower and nearer Dome de Gouter (so often, when clouds are about, mistaken for the true summit by tourists) had assumed a marvellous shade of saffron-rose colour. The crevasses of the glaciers were marked by an unearthly pale-green tint and delicate purple hues of weird beauty were spreading over the evanescent forms of the great snow-field, when one of the hotel guests--a citizen of Geneva--said, “Ah, yes! Look at them whilst you may, and wonder at them, those glaciers of the Alps. They are but the remnants, the roots, as it were, of the vast glacier which once filled the whole of this vale of Chamonix and spread down into the valley of the Rhone, and ploughed out with the slow movement of its huge mass the deep rock basin of the Lake Leman. Every year they dwindle, as they have dwindled for ages past, and soon--perhaps not more than another 100 years hence--they will have disappeared utterly from human sight and knowledge.” I continued to gaze at the scene, and as the night fell and the distant details were lost to view I felt as though a venerable, but decrepit, friend had passed from my sight, never to return. I was rejoiced to see the glaciers still there when the morning sun showed forth their strange opaque white and faintly green masses on the mountain sides--stupendous outpourings, as it were, of whipped cream tinted with pistachio-nut.
But was it true, that lament of the Genevese savant? Undoubtedly the glaciers in many parts of the Alps have been shrinking for the last thirty years. It is longer than that since I first saw the glaciers of the Chamonix valley, and there is no doubt that they have shrunk up since then, leaving acres of boulders and bare polished rock where was the ice I formerly climbed. The glacier of Argentière, near the upper end of the valley, is a mile or more shorter than it was; the ice caves which we used to visit at the foot of the Mer de Glace have melted away, and the end of the glacier is now high up above a precipitous surface of polished rock far from the site of the little pavilion, with its gay flag and amiable guardian, who used to exhibit the marvellous ice cavern.
I find on looking into the matter that it is true that there has, during the latter half of the past century, been a great dwindling of the lower end or “snout,” a drawing back, as it were, not only of Swiss glaciers, but of glaciers in other parts of the world--as, for instance, in Alaska and in the Himalayas. But I cannot avoid a feeling of satisfaction in recording the opinion of geological authorities that, contrary to the assertion of the Swiss pessimist, there is not any ground for believing that the present noticeable shrinking is due to a continuous process by which the enormous glaciers of remote ages have been incessantly reduced until now they are but rootlets or stumps of the former masses, destined to evaporate completely under the continued remorseless operation of increasing temperature. On the contrary, it appears that, though there are not accurate records and measurements as to past centuries as there will be as to present and future years, yet there is abundant evidence that Alpine glaciers have grown longer in some centuries and retreated in others. The period of alternate extension and retraction has not been ascertained with accuracy, but by some geologists it is supposed to be about fifty years. The retraction or shrinking is not due to a continuous increase of the temperature of the earth’s atmosphere--or of this hemisphere--but to contending causes which operate alternately towards increase and towards decrease when one or two hundred years are considered. Such are the greater or less rainfall and snowfall over a very large area, and the formation and persistence of clouds, concerned with which are probably those varying quantities--the spots on the sun.
The simple proof that glaciers have extended and again retreated within historic times is furnished by the fact that in some parts of the Alpine range the retreat of a glacier has uncovered ancient miners’ excavations, which must have been worked when the glacier did not reach the spot excavated. Subsequently the glacier advanced, and now after some hundreds of years it has again retreated and exposed the ice-covered borings and workings. The tradition of a glacier-enclosed village in the Zermatt mountains, shut off from the world by the advance of glaciers, lost and mysterious, is evidence that such advance has been observed by the native population.
The natives who live near glaciers know that they advance and retreat, but the fact that the whole glacier is really a slowly flowing viscous mass--a sort of frozen but not immobile river--was only established by scientific observation in the last century. The frozen river is fed by the snow which falls on the higher mountain ridges, and is squeezed into the form of ice instead of snow powder by its own weight as it slips down the inclines, warmed by the unclouded sunshine. The big glaciers move much more rapidly (or perhaps one should say less slowly) in the middle than at the sides. The measurements which have been made differ in different glaciers and in different parts of the same glacier, and show smaller movement in winter than in summer. The advance of the sides is retarded, as in the case of an ordinary river of flowing water, by friction against the rocks, which enclose the glacier as its banks enclose a river. A good average case shows a flow downwards in summer of half a foot a day at the sides and a foot and a half in the middle. The distance below the snow-line to which the flowing glacier descends down a mountain gorge--before it melts away and becomes a river of liquid water--depends, as does the rate at which it moves, in the first place, on the temperature of the region and on the sharpness of the slope. A glacier will flow downwards (as will a lump of pitch) along a scarcely perceptible incline, but more slowly than down a steeper incline, and it will, consequently, get further down into the warm valley without altogether melting away when the slope is steep.
But apart from these considerations, the bigger and thicker (or deeper) the glacier, that is to say, the more snow which each year falls at its starting-place and goes to making it, the further down will it flow before melting away; and it is the heavy snowfall of many years ago or of a series of years long past which has to-day reached in the form of ice the lower end of the glacier. So, though the lower end of the glacier may melt more quickly if the valley has become hotter, yet the heavy snowfalls of fifty years ago may only now have reached the valley, and may quite counterbalance the melting action of the warmer summers. Or reverse conditions, namely, less snow and lower or unchanged temperature in the valley, may prevail.