The World's Greatest Books - Volume 15 Part 10

_IV.--Practical Eugenics_

The following are some views of my own relating to that large province of eugenics which is concerned with favouring the families of those who are exceptionally fit for citizens.h.i.+p. Consequently, little or nothing will here be said relating to what has been well termed by Dr. Saleeby "negative" eugenics, namely, the hindrance of the marriages and the production of offspring by the exceptionally unfit. The latter is unquestionably the more pressing subject, but it will soon be forced on the attention of the legislature by the recent report of the Royal Commission on the Feeble-minded.

Whatever scheme of action is proposed for adoption must be neither Utopian nor extravagant, but accordant throughout with British sentiment and practice.

By "worth" I mean the civic worthiness, or the value to the state, of a person. Speaking only for myself, if I had to cla.s.sify persons according to worth, I should consider each of them under the three heads of physique, ability and character, subject to the provision that inferiority in any one of the three should outweigh superiority in the other two. I rank physique first, because it is not only very valuable in itself and allied to many other good qualities, but has the additional merit of being easily rated. Ability I place second on similar grounds, and character third, though in real importance it stands first of all.

The power of social opinion is apt to be underrated rather than overrated. Like the atmosphere which we breathe and in which we move, social opinion operates powerfully without our being conscious of its weight. Everyone knows that governments, manners, and beliefs which were thought to be right, decorous, and true at one period have been judged wrong, indecorous, and false at another; and that views which we have heard expressed by those in authority over us in early life tend to become axiomatic and unchangeable in mature life.

In circ.u.mscribed communities especially, social approval and disapproval exert a potent force. Is it, then, I ask, too much to expect that when a public opinion in favour of eugenics has once taken sure hold of such communities, the result will be manifested in sundry and very effective modes of action which are as yet untried?

Speaking for myself only, I look forward to local eugenic action in numerous directions, of which I will now specify one. It is the acc.u.mulation of considerable funds to start young couples of "worthy"

qualities in their married life, and to a.s.sist them and their families at critical times. The charitable gifts to those who are the reverse of "worthy" are enormous in amount. I am not prepared to say how much of this is judiciously spent, or in what ways, but merely quote the fact to justify the inference that many persons who are willing to give freely at the prompting of a sentiment based upon compa.s.sion might be persuaded to give largely also in response to the more virile desire of promoting the natural gifts and the national efficiency of future generations.

_V.--Eugenics as a Factor in Religion_

Eugenics strengthen the sense of social duty in so many important particulars that the conclusions derived from its study ought to find a welcome home in every tolerant religion. It promotes a far-sighted philanthropy, the acceptance of parentage as a serious responsibility, and a higher conception of patriotism. The creed of eugenics is founded upon the idea of evolution; not on a pa.s.sive form of it, but on one that can, to some extent, direct its own course.

Purely pa.s.sive, or what may be styled mechanical evolution displays the awe-inspiring spectacle of a vast eddy of organic turmoil, originating we know not how, and travelling we know not whither. It forms a continuous whole, but it is moulded by blind and wasteful processes--namely, by an extravagant production of raw material and the ruthless rejection of all that is superfluous, through the blundering steps of trial and error.

The condition at each successive moment of this huge system, as it issues from the already quiet past and is about to invade the still undisturbed future, is one of violent internal commotion. Its elements are in constant flux and change.

Evolution is in any case a grand phantasmagoria, but it a.s.sumes an infinitely more interesting aspect under the knowledge that the intelligent action of the human will is, in some small measure, capable of guiding its course. Man has the power of doing this largely so far as the evolution of humanity is concerned; he has already affected the quality and distribution of organic life so widely that the changes on the surface of the earth, merely through his disforestings and agriculture, would be recognisable from a distance as great as that of the moon.

As regards the practical side of eugenics, we need not linger to reopen the unending argument whether man possesses any creative power of will at all, or whether his will is not also predetermined by blind forces or by intelligent agencies behind the veil, and whether the belief that man can act independently is more than a mere illusion.

Eugenic belief extends the function of philanthropy to future generations; it renders its action more pervading than hitherto, by dealing with families and societies in their entirety, and it enforces the importance of the marriage covenant by directing serious attention to the probable quality of the future offspring. It sternly forbids all forms of sentimental charity that are harmful to the race, while it eagerly seeks opportunity for acts of personal kindness. It strongly encourages love and interest in family and race. In brief, eugenics is a virile creed, full of hopefulness, and appealing to many of the n.o.blest feelings of our nature.

ERNST HAECKEL

The Evolution of Man

Ernst Haeckel, who was born in Potsdam, Germany, Feb. 16, 1834, descends from a long line of lawyers and politicians. To his father's annoyance, he turned to science, and graduated in medicine. After a long tour in Italy in 1859, during which he wavered between art and science, he decided for zoology, and made a masterly study of a little-known group of sea-animalcules, the Radiolaria. In 1861 he began to teach zoology at Jena University.

Darwin's "Origin of Species" had just been translated into German, and he took up the defence of Darwinism against almost the whole of his colleagues. His first large work on evolution, "General Morphology," was published in 1866. He has since published forty-two distinct works. He is not only a master of zoology, but has a good command of botany and embryology. Haeckel's "Evolution of Man" (Anthropogenie), is generally accepted as being his most important production. Published in 1874, at a time when the theory of natural evolution had few supporters in Germany, the work was hailed with a storm of controversy, one celebrated critic declaring that it was a blot on the escutcheon of Germany. From the hands of English scientists, however, the treatise received a warm welcome.

Darwin said he would probably never have written his "Descent of Man" had Haeckel published his work earlier.

_I.--The Science of Man_

The natural history of mankind, or anthropology, must always excite the most lively interest, and no part of the science is more attractive than that which deals with the question of man's origin. In order to study this with full profit, we must combine the results of two sciences, ontogeny (or embryology) and phylogeny (the science of evolution). We do this because we have now discovered that the forms through which the embryo pa.s.ses in its development correspond roughly to the series of forms in its ancestral development. The correspondence is by no means complete or precise, since the embryonic life itself has been modified in the course of time; but the general law is now very widely accepted.

I have called it "the biogenetic law," and will constantly appeal to it in the course of this study.

It is only in recent times that the two sciences have advanced sufficiently to reveal the correspondence of the two series of forms.

Aristotle provided a good foundation for embryology, and made some interesting discoveries, but no progress was made in the science for 2,000 years after him. Then the Reformation brought some liberty of research, and in the seventeenth century several works were written on embryology.

For more than a hundred years the science was still hampered by the lack of good microscopes. It was generally believed that all the organs of the body existed, packed in a tiny point of s.p.a.ce, in the germ. About the middle of the eighteenth century, Caspar Friedrich Wolff discovered the true development; but his work was ignored, and it was only fifty years later that modern embryology began to work on the right line. K.E.

von Baer made it clear that the fertilised ovum divides into a group of cells, and that the various organs of the body are developed from these layers of cells, in the way I shall presently describe.

The science of phylogeny, or, as it is popularly called, the evolution of species, had an equally slow growth. On the ground of the Mosaic narrative, no less than in view of the actual appearance of the living world, the great naturalist Linne (1735) set up the dogma of the unchangeability of species. Even when quite different remains of animals were discovered by the advancing science of geology, they were forced into the existing narrow framework of science by Cuvier. Sir Charles Lyell completely undid the fallacious work of Cuvier, but in the meantime the zoologists themselves were moving toward the doctrine of evolution.

Jean Lamarck made the first systematic attempt to expound the theory in his "Zoological Philosophy" (1809). He suggested that animals modified their organs by use or disuse, and that the effect of this was inherited. In the course of time these inherited modifications reached such a pitch that the organism fell into a new "species." Goethe also made some remarkable contributions to the science of evolution. But it was reserved for Charles Darwin to win an enduring place in science for the theory. "The Origin of Species" (1859) not only sustained it with a wealth of positive knowledge which Lamarck did not command, but it provided a more luminous explanation in the doctrine of natural selection. Huxley (1863) followed with an application of the law to man, and in 1866 I gave a comprehensive sketch of its application throughout the whole animal world. In 1874 I published the first edition of the present work.

The doctrine of evolution is now a vital part of biology, and we might accept the evolution of man as a special deduction from the general law.

Three great groups of evidence impose that law on us. The first group consists of the facts of palaeontology, or the fossil record of past animal life. Imperfect as the record is, it shows us a broad divergence of successively changing types from a simple common root, and in some cases exhibits the complete transition from one type to another. The next doc.u.ment is the evidence of comparative anatomy. This science groups the forms of living animals in such a way that we seem to have the same gradual divergence of types from simple common ancestors. In particular, it discovers certain rudimentary organs in the higher animals, which can only be understood as the shrunken relics of organs that were once useful to a remote ancestor. Thus, man has still the rudiment of the third eyelid of his shark-ancestor. The third doc.u.ment is the evidence of embryology, which shows us the higher organism substantially reproducing, in its embryonic development, the long series of ancestral forms.

_II.--Man's Embryonic Development_

The first stage in the development of any animal is the tiny speck of plasm, hardly visible to the naked eye, which we call the ovum, or egg-cell. It is a single cell, recalling the earliest single-celled ancestor of all animals. In its immature form it is not unlike certain microscopic animalcules known as _amoeboe_. In its mature form it is about 1/125th of an inch in diameter.

When the male germ has blended with the female in the ovum, the new cell slowly divides into two, with a very complicated division of the material composing its nucleus. The two cells divide into four, the four into eight, and so on until we have a round cl.u.s.ter of cells, something like a blackberry in shape.

This _morula_, as I have called it, reproduces the next stage in the development of life. As all animals pa.s.s through it, our biogenetic law forces us to see in it an ancestral stage; and in point of fact we have animals of this type living in Nature to-day. The round cl.u.s.ter becomes filled with fluid, and we have a hollow sphere of cells, which I call the _blastula_. The corresponding early ancestor I name the _Blastaea_, and again we find examples of it, like the _Volvox_ of the ponds, in Nature to-day.

The next step is very important. The hollow sphere closes in on itself, as when an india rubber ball is pressed into the form of a cup. We have then a vase-shaped body with two layers of cells, an inner and an outer, and an opening. The inner layer we call the entoderm, the outer the ectoderm; and the "primitive mouth" is known as the blastopore. In the higher animals a good deal of food-yolk is stored up in the germ, and so the vase-shaped structure has been flattened and altered. It has, however, been shown that all embryos pa.s.s through this stage (gastrulation), and we again infer the existence of a common ancestor of that type--the _Gastraea_. The lowest group of many-celled animals--the corals, jelly-fishes, and anemones--are essentially of that structure.

The embryo now consists of two layers of cells, the "germ-layers," an inner and outer. As the higher embryo develops, a third layer of cells now pushes between the two. We may say, broadly, that from this middle layer are developed most of the animal organs of the body; from the internal germ-layer is developed the lining of the alimentary ca.n.a.l and its dependent glands; from the outer layer are formed the skin and the nervous system--which developed originally in the skin.

The embryo of man and all the other higher animals now develops a cavity, a pair of pouches, by the folding of the layer at the primitive mouth. Sir E. Ray Lankester, and Professor Balfour, and other students, traced this formation through the whole embryonic world, and we are therefore again obliged to see in it a reminiscence of an ancestral form--a primitive worm-like animal, of a type we shall see later. The next step is the formation of the first trace of what will ultimately be the backbone. It consists at first of a membraneous tube, formed by the folding of the inner layer along the axis of the embryo-body. Later this tube will become cartilage, and in the higher animals the cartilage will give place to bone.

The other organs of the body now gradually form from the germ-layers, princ.i.p.ally by the folding of the layers into tubes. A light area appears on the surface of the germ. A streak or groove forms along its axis, and becomes the nerve-cord running along the back. Cube-shaped structures make their appearance on either side of it; these prove to be the rudiments of the vertebrae--or separate bones of the backbone--and gradually close round the cord. The heart is at first merely a spindle-shaped enlargement of the main ventral blood-vessel. The nose is at first only a pair of depressions in the skin above the mouth.

When the human embryo is only a quarter of an inch in length, it has gill-clefts and gill-arches in the throat like a fish, and no limbs. The heart--as yet with only the simple two-chambered structure of a fish's heart--is up in the throat--as in the fish--and the princ.i.p.al arteries run to the gill-slits. These structures never have any utility in man or the other land-animals, though the embryo always has them for a time.

They point clearly to a fish ancestor.

Later, they break up, the limbs sprout out like blunt fins at the sides, and the long tail begins to decrease. By the twelfth week the human frame is perfectly formed, though less than two inches long. Last of all, it retains its resemblance to the ape. In the embryonic apparatus, too, man closely resembles the higher ape.

_III.--Our Ancestral Tree_

The series of forms which we thus trace in man's embryonic development corresponds to the ancestral series which we would a.s.sign to man on the evidence of palaeontology and comparative anatomy. At one time, the tracing of this ancestral series encountered a very serious check. When we examined the groups of living animals, we found none that ill.u.s.trated or explained the pa.s.sage from the non-backboned--invertebrate--to the backboned--vertebrate--animals. This gap was filled some years ago by the discovery of the lancelet--_Amphioxus_--and the young of the sea-squirt--_Ascidia_. The lancelet has a slender rod of cartilage along its back, and corresponds very closely with the ideal I have sketched of our primitive backboned ancestor. It may be an offshoot from the same group. The sea-squirt further ill.u.s.trates the origin of the backbone, since it has a similar rod of cartilage in its youth, and loses it, by degeneration, in its maturity.

In this way the chief difficulty was overcome, and it was possible to sketch the probable series of our ancestors. It must be well understood that not only is the whole series conjectural, but no living animal must be regarded as an ancestral form. The parental types have long been extinct, and we may, at the most, use very conservative living types to ill.u.s.trate their nature, just as, in the matter of languages, German is not the parent, but the cousin of Anglo-Saxon, or Greek of Latin. The original parental languages are lost. But a language like Sanscrit survives to give us a good idea of the type.

The law of evolution is based on such a ma.s.s of evidence that we may justly draw deductions from it, where the direct evidence is incomplete.

This is especially necessary in the early part of our ancestral tree, because the fossil record quite fails us. For millions of years the early soft-bodied animals left no trace in the primitive mud, which time has hardened into rocks, and we are restricted to the evidence of embryology and of comparative zoology. This suffices to give us a general idea of the line of development.

In nature to-day, one of the lowest animal forms is a tiny speck of living plasm called the _amoeba_. We have still more elementary forms, such as the minute particles which make up the bluish film on damp rocks, but they are of a vegetal character, or below it. They give us some idea of the very earliest forms of life; minute living particles, with no organs, down to the ten-thousandth part of an inch in diameter.

The amoeba represents the lowest animal, and, as we saw, the ovum in many cases resembles an amoeba. We therefore take some such one-celled creature as our first animal ancestor. Taking food in at all parts of its surface, having no permanent organs of locomotion, and reproducing by merely splitting into two, it exhibits the lowest level of animal life.

The next step in development would be the cl.u.s.tering together of these primitive microbes as they divided. This is actually the stage that comes next in the development of the germ, and it is the next stage upward in the existing animal world. We a.s.sume that these cl.u.s.ters of microbes--or cells, as we will now call them--bent inward, as we saw the embryo do, and became two-layered, cup-shaped organisms, with a hollow interior (primitive stomach) and an aperture (primitive mouth). The inner cells now do the work of digestion alone; the outer cells effect locomotion, by means of lashes like oars, and are sensitive. This is, in the main, the structure of the next great group of animals, the hydra, coral, meduca, and anemone. They have remained at this level, though they have developed, special organs for stinging their prey and bringing the food into their mouths.

Both zoology and the appearance of the embryo point to a worm-like animal as the next stage. Constant swimming in the water would give the animal a definite head, with special groups of nerve-cells, a definite tail, and a two-sided or evenly-balanced body.