Science from an Easy Chair E-Book

Sir E. Ray Lankester

• Herausgeber: Books on Demand
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2020

Beschreibung

The delight which is experienced by those who discover new things in the various branches of science is, no doubt, very great. To reveal to other men processes, properties, existences in the natural world hitherto unsuspected, or, if suspected, yet eluding the grasp of man, is to do something which gives to him who does it a sense that he is of value in the world-a sense which will uphold him and enable him to endure adversity, and even persecution, with equanimity. But there is, perhaps, a greater and more vivid satisfaction for those who do or make great and splendid things which all men can see, and for which all men are grateful. The great artist-poet, painter, builder, or musician-has this satisfaction, and so also has the man who, by a combination of personal energy and clearness of intellectual vision, applies scientific knowledge to the accomplishment of great public works, and to the acquirement of that control by mankind of the natural conditions hostile to human progress which we may call, as did Lord Bacon, "the establishing of the kingdom of man."

Leseprobe

Science from an Easy Chair

Science from an Easy ChairI SCIENCE AND PRACTICEII UNIVERSITY TRAININGIII DARWIN’S THEORYIV DARWIN’S DISCOVERIESV DARWIN’S THEORY UNSHAKENVI METCHNIKOFF AND TOLSTOIVII THE LAND OF AZURE BLUEVIII FRESH-WATER JELLY-FISHESIX THE STORY OF THE COMMON EELX MODERN HORSES AND THEIR ANCESTORSXI A RIVAL OF THE FABLED UPAS TREEXII POISONS AND STINGS OF PLANTS AND ANIMALSXIII THE DRAGON: A FANCY OR A FACTXIV OYSTERSXV MATERNAL CARE AND MOLLUSCSXVI THE HEART’S BEATXVII SLEEPXVIII THE UNIVERSAL STRUCTURE OF LIVING THINGSXIX PROTOPLASM, LIFE AND DEATHXX CHEMISTRY AND PROTOPLASMXXI THE SIMPLEST LIVING THINGSXXII TADPOLES AND FROGSXXIII ABOUT THE STARSXXIV COMETSXXV ABOUT CHOLERAXXVI SEA-BREEZES, MOUNTAIN AIR, AND OZONEXXVII OXYGEN GAS FOR ATHLETES AND OTHERSXXVIII SPARROWS, TROUT, AND SELECTIVE BREEDINGXXIX THE FEEBLE-MINDEDXXX DEATH-RATESXXXI GOSSAMERXXXII THE JUMPING BEANXXXIII PROTECTIVE COLOURING IN ANIMALSXXXIV HOP-BLIGHTXXXV GREEN-FLIES, PLANT-LICE, AND PARTHENOGENESISXXXVI THE DEADLY PHYLLOXERAXXXVII CLOTHES MOTHSXXXVIII STONE AND WOOD BORERSXXXIX CHRISTMAS FAREXL THE ORIGIN OF OPIUMXLI THE MOST ANCIENT MENXLII THE CAVE-MEN’S SKULLSXLIII MORE ABOUT THE NEANDER MENCopyright

Science from an Easy Chair

Sir E. Ray Lankester

I SCIENCE AND PRACTICE

I SCIENCE AND PRACTICE

The delight which is experienced by those who discover new things in the various branches of science is, no doubt, very great. To reveal to other men processes, properties, existences in the natural world hitherto unsuspected, or, if suspected, yet eluding the grasp of man, is to do something which gives to him who does it a sense that he is of value in the world—a sense which will uphold him and enable him to endure adversity, and even persecution, with equanimity. But there is, perhaps, a greater and more vivid satisfaction for those who do or make great and splendid things which all men can see, and for which all men are grateful. The great artist—poet, painter, builder, or musician—has this satisfaction, and so also has the man who, by a combination of personal energy and clearness of intellectual vision, applies scientific knowledge to the accomplishment of great public works, and to the acquirement of that control by mankind of the natural conditions hostile to human progress which we may call, as did Lord Bacon, “the establishing of the kingdom of man.”

The men who have expelled yellow fever from Cuba and Panama have not merely done a piece of sanitary cleaning up; they have first imagined and then created, by the force of human will, directed and maintained by conviction of the reality of science, a new thing—the tropics without deadly fever, the tropics as a healthy and welcome home for the white man. That is comparable to the work of a great artist in the directness of its appeal; it is in its actual detail the result of the combination of the skill of the engineer with the foresight and absolute domination of his human agents of a military genius.

For this magnificent work the highest credit is due to the United States chief sanitary officer, Colonel Gorgas. It is well known how the American Medical Commission in Cuba proved six years ago that yellow fever is conveyed from man to man solely and entirely by a gnat common in Central America, known as Stegomyia, and further, how by carrying out measures for preventing the entrance of these gnats into dwelling-houses, and especially by keeping them away from yellow fever patients so that they fail to obtain and carry the yellow fever germ, even if they do bite healthy men, Colonel Gorgas and his associates practically eradicated yellow fever in Cuba. The bite of the Stegomyia gnat is the only way in which a man can acquire yellow fever, and the gnat which bites him must have taken up the germs of yellow fever from another man—twelve days (no less) previously.

The application of this knowledge and the methods devised to give it effect is what has now rendered the construction of the Panama Canal by the United States Government possible. The French Canal Company employed an army of labourers, numbering from 15,000 to 18,000 men. They lost, almost entirely by death from yellow fever and malaria, so many of their workmen that others refused to undertake the deadly job, and there was a general panic. The death-rate was in 1884 over 60 per 1000. In 1885 it was over 70 per 1000. The work was abandoned. In May 1904 Colonel Gorgas and his forces took possession of the canal zone. This is a zone of territory running fifty miles north and south, with a good-sized town—Colon—at one end of it and another—Panama—at the other end of it. Many hundreds of men were at once organised and set to work to destroy in both the towns the Stegomyia gnat. This was effected by doing away with all the breeding-places of the gnat, that is, screening and covering every water receptacle in the town, so that the gnats or mosquitoes cannot breed. Then a fumigating process was carried out in all houses and buildings, great and small, to destroy such gnats as were still alive. No less than 200,000 lb. of pyrethrum and 400,000 lb. of sulphur were used in this fumigation. In December 1905 the last case of yellow fever occurred. It took sixteen months of the work just described to effect this.

In a different way the Anopheles gnat or mosquito, which carries the germ of malaria from man to man, was got rid of. This gnat breeds in clean water, where grass and weeds grow; it belongs chiefly to country districts. As it rarely flies more than 200 yards it was sufficient to destroy the breeding pools within that distance of the workmen’s houses, camps, and villages. All the windows and doors of all houses were fitted with wire-gauze screens, which prevent the entrance of the gnats, and the population was furnished with quinin, a dose of 3 grs. a day being ordered to bring the men into such condition that the malaria parasite would not thrive in the blood even if introduced.

The object with which Colonel Gorgas and his associates started was accomplished in less than two years. The control of yellow fever and malaria has become even more complete in the two years which have followed. It is two years since yellow fever disappeared from the entire zone, including the two towns. Malaria has not been so completely destroyed. The employés of the Canal Commission and Panama Railway now number 45,000. The death-rate of this entire force, including both black (33,000) and white (12,000) employés, was, in the month of December 1907 only 18 per 1000 per annum—less than that of the city of Liverpool, which was 20, or that of Salford, which was over 19. Of all the white employés the death-rate was only 13 per 1000 per annum. In the year 1906 (whole year), among the 6000 white employés who had come from the United States, including some 1200 women and children, their families, the death-rate from disease was only 4 per 1000. Pneumonia has been a chief cause of death among the negro labourers, but seldom affects the whites. Malaria caused, in the whole army of labourers, only six deaths in December 1907, as against thirteen in the smaller army at work in the same month in 1906. There were 800 cases of malaria in the whole army of 45,000 employés in December 1907.

It is thus apparent that Colonel Gorgas has converted this deadly zone from which negroes and white men hurried in a panic of fear twenty years ago into a region as healthy—that is to say, with as low a death-rate—as an ordinary North American or English city. No doubt allowance must be made in the comparison for the special nature of the population brought together on the canal zone. This is favourable to a low death-rate, in so far as it consists of strong adults, excluding old people and very young children, but unfavourable in so far as it consists of negroes and mean whites, who are even less amenable to sanitary regulations and precautions than the population of an English city. Colonel Gorgas writes that now that it is shown that any population coming into the tropics can protect itself against yellow fever and malaria by measures which are both simple and inexpensive, the Anglo-Saxon will find life in the tropics more healthful than in the temperate zones, and tropical countries which offer a much greater return for man’s labour than do those of the chilly temperate zone, will be in the course of the next two or three centuries occupied and populated by the white races. Such an unpleasantly cold spring as that which all Europe endured last year makes one wish that the tropics generally were already arranged by Colonel Gorgas for our reception, and provided with a sanitated white-faced population. We could go and live there, warm and comfortable, all the year round, enjoying the rich luxuriance of tropical nature without fear of either chill or fever.

II UNIVERSITY TRAINING

II UNIVERSITY TRAINING

At Manchester last year, when they installed Lord Morley, the Secretary of State for India, as Chancellor of the University, the Right Hon. Arthur Balfour delivered a very interesting address, in which he declared himself a believer in the gospel of “Science the Master.” Mr. Balfour’s speech did not imply any disregard for the pursuit of historical knowledge and a training in literature and the use of language, but it was a clear recognition of the fact that when the great purpose for which universities exist is considered it must be asserted in no hesitating terms that the discovery of new knowledge is the most important activity which a university can foster. To train men (and women, too) to use their faculties not merely to acquire knowledge of what has been discovered by others in the past, but to discover new things and to gain further control over the conditions in which we live, and to secure further understanding not only of nature but of man—that is the great business of the university.

It was fortunate that Mr. Balfour was present and able to strike this note, for Lord Morley, the new Chancellor, had not expressed any such conception of the aims of a university. He declared that, so long as the Greeks have anything to teach us we should not cease to study the Greeks. But, whilst we may agree to this, it is well to remember that, though pleasure can still be obtained from Greek poetry and prose by those who have thoroughly mastered the Greek language, yet almost all, if not quite all, that the Greeks have to teach us has been by this time translated and dealt with by our own writers. Consequently, although we may cordially approve of the study of ancient civilisations and ancient literatures and languages, both Greek and barbarian, as part of the enterprise of a university, it is somewhat excessive, not to say belated, to set up the study of Greek or of any other historic language and civilisation as the chief and distinctive boon which universities can offer to their scholars. The matter has, indeed, been thrashed out, and Greek, together with what is called the “study of literature” (but is usually an ineffective dabbling in it), has been put into its proper subordinate place in all the universities of Europe and in most of those of Great Britain. The illusion that flowers of speech and mastery of phrase (though all very well if honestly used) are an indication of any knowledge or capacity which can be of service to the community, has been, in late years, to a very large extent, dispelled.

The concluding words of Mr. Balfour’s speech were: “The great advancement of mankind is to be looked for in our ever-increasing knowledge of the secrets of nature—secrets, however, which are not to be unlocked by the men who pursue them for purely material ends, but secrets which are open in their fulness only to men who pursue them in a disinterested spirit. The motive power which is really going to change the external surface of civilisation, which is going to add to the well-being of mankind, which is going to stimulate the imagination of all those who are interested in the universe in which our lot is cast—that lies after all with science. I would rather be known as having added to the sum of our knowledge of the truth of nature than anything else I can imagine. Unfortunately for me, my opportunities have lain in different directions.”

That is a splendid confession of faith. I do not remember that any German statesman of like authority and standing has ever given expression to so full and ample a belief in the value of science. Yet German statesmen have acted, though they have not spoken. They have arranged for, and continually are arranging for, a far larger expenditure of public money upon scientific training and investigation than is assigned to such purposes in this country. Every department of government in Germany has its thoroughly trained, well-taught, well-paid body of scientific experts and investigators, and, moreover, the whole official world, from the Emperor downwards, has a real understanding of what science is, of the folly of attempting to proceed without it, or allowing persons who are ignorant of it to act as administrators. The need for science is not merely recognised in words, but steps are taken, and have been taken now for many years, actually to secure in German public offices and public administration the predominance of that scientific knowledge which the German statesmen, as well as Mr. Balfour, consider so necessary. Is it too much to hope that in this country those who recognise the value and importance of scientific knowledge will also take steps to re-arrange our Government departments so as to give them the advantage of guidance by men trained in the knowledge of nature, rather than by men ignorant of the very existence of such knowledge?

The universities hold the central position in this matter, and it is their influence and wealth which the State should insist on directing towards the extension and diffusion of science. Those who address the public on this subject not infrequently take what seems to me to be a disastrous line at the start. They speak of the new universities as the universities of the people, and hand over Oxford and Cambridge, with their enormous endowments, their history and tradition, to the wealthy class. Such usurpation cannot be tolerated. It is monstrous that the endowments of the colleges of Oxford and Cambridge, which were thoroughly popular and democratic in their foundation, should be, even for a moment, regarded as the peculiar property of the wealthy. It is also monstrous to suppose that it is anything less than disastrous to consign the well-to-do classes in any community to an empty sham of ancient “culture” rather than to imbue them with the real and inspiring culture of the modern renaissance. It is because this notion is allowed to gain ground that the enormous funds of the colleges and universities of Oxford and Cambridge, amounting to more than three-quarters of a million pounds annually, are to a large extent, though not exclusively, employed in keeping up a couple of huge boarding-schools, which are shut for six months in the year.

It is owing to this that it is the rarest thing to find in Oxford or in Cambridge a great teacher who lectures or demonstrates to an eager following of disciples. An overwhelming majority of the young men who go as students to these universities have no intention of studying anything. They are sent there in order to be submitted to college discipline and to have, subject to that safeguard, a good time. A large number are handsomely paid by scholarships in order to induce them to go there—and would not go there at all unless they were so paid. They do not find such teachers there and such an effective occupation of their student years as would induce them, if unpaid, to seek the university, or to pay fees out of their own pockets for the opportunities of seriously pursuing any branch of learning or science within its walls.

The inefficiency of the old universities is to a large extent the cause of the neglect and ignorance of science in the well-to-do class, who furnish the men who become Government officials of all kinds and members of professions which influence public opinion. But this inefficiency of the old universities is not due to their devotion to literary studies and to abstract science, nor to their objection to the pursuit of practical and commercial studies. That excuse is sometimes put forward for them, though at this moment they are, in fact, setting up laboratories and lecture-rooms for engineering, agriculture, forestry, mining, and such applications of science. Nor is it money which is really wanting at either Oxford or Cambridge, although they are both begging for it from the public. What Oxford and Cambridge want is not money but men; men as teachers—“professors” is the usual title given to them in a university—who must be the ablest, each in his own line, in the whole world. If such professors existed in either Oxford or Cambridge, and were allowed to teach, the town (if not the colleges!) would be full to overflowing of students—eager to pay their fees and to spend, not three short terms of seven weeks in each year, but the whole year, and many years, in the laboratories and lecture-rooms of those commanding men.

To obtain such men—to set the machinery at work—you must pay them handsomely, and give them authority and the means of work. Once they were at work, the mere fees of the students would furnish a splendid revenue. There is plenty of money at Oxford and at Cambridge—a superabundance, in fact—which could and should be applied to this purpose, namely, that of securing and establishing there the greatest teachers in the world. The money is at present administered by the colleges according to the directions given in recent Acts of Parliament, and by no means in any blind obedience to the original intentions of the founders of the colleges. It is to a large extent wasted. That portion of it paid out as “scholarships” is for the most part wasted in bringing students to a place where they cannot get the best opportunities of study, and the rest is unwisely applied (not so much by the tenants for life or administrators of college funds as by rigid Act of Parliament) to providing an excessive number of totally inadequate salaries by which a corresponding number of young men are induced to enter upon the career of teachers as underpaid college Fellows.

III DARWIN’S THEORY

III DARWIN’S THEORY

On Wednesday, the 1st of July 1908, half a century had passed since Darwin’s Theory of the Origin of Species was made known to the world. Fifty years have now been completed since that immortal book, The Origin of Species, was published, and a hundred years since Charles Darwin was born.

It is not every one who is in a position to understand how great and momentous was the occasion when Sir Charles Lyell and Dr. Joseph Hooker communicated to the Linnean Society of London, on the 1st of July 1858, two papers, one by Charles Darwin, the other by Alfred Russel Wallace, under the common title, “On the Tendency of Species to form Varieties: and on the Perpetuation of Varieties and Species by Natural means of Selection.” The reason for this conjoint communication to the Linnean Society was that Darwin, who had been working for years at the subject, and had already, in 1842, drawn up a statement of his theory, not for publication, but for the consideration and criticism of his friend Hooker—unexpectedly received from Alfred Russel Wallace, who was, and had been for some years, away in the Malay Archipelago—a manuscript of an essay on the origin of species, containing views identical with his own, and even phrases similar to those he had himself found it necessary to invent. Thus Wallace speaks of the “struggle for existence,” whilst Darwin had used the term “struggle for life.” Darwin had been urged by his friends before this to publish an abstract or statement of his conclusions, but now that he had received Wallace’s manuscript, he declared in a letter to Hooker, “I would far rather burn my whole book than that he or any other man should think that I had behaved in a paltry spirit.” And so Lyell and Hooker took the matter in hand, and communicated to the Linnean Society, accompanied by an explanatory statement, the two independent papers, setting forth, as they say, “the results of the investigations of the indefatigable naturalists, Mr. Charles Darwin and Mr. Alfred Wallace.” Such loyalty and regard to each other as Darwin and Wallace showed then and ever after form a delightful feature in the history of this great discovery. A wonderful thing is that Hooker, now Sir Joseph Hooker, the greatest botanist of the past century, the constant friend and comrade of Darwin, is still alive, and that Alfred Russel Wallace, too, is still with us. They both were present when the Linnean Society celebrated the meeting of fifty years ago.

The views of Darwin and Wallace have now become the established doctrine of science. They have led to the universal recognition of “the origin of species by descent with modification.” That is a statement, in other words, to the effect that all the various kinds of living things have been gradually produced by natural birth from predecessors which differ from them only slightly in the later stages of time, but become simpler and less like their descendants as we go further back, until we reach the simplest living things. It has led to the conviction that there has been no exceptional or “miraculous” suspension of the order of Nature in this process, but that all has come about in due and regular course, in virtue of the properties of natural things, which we know as the laws of physics and chemistry. Most important and dominating of all these results is the inevitable one that man himself has come from animal ancestors, in the same way, and—(this is the greatest and most far-reaching conclusion of all)—that he is still subject to those natural processes of change and development by which he has reached his present phase; that he must completely understand them and control them (so far as such control is possible) in order to maintain a healthy, happy, and improving race of men on the face of the globe. This great possession—the earth and all that lives on it—is, as Lord Bacon phrased it three hundred years ago—the Kingdom of Man. Man has but to use his intelligence in order to take control of it. The knowledge of his own relation to it, and of the ways in which the human race is affected for good and for ill, through the operation of the self-same processes which affect the breeding, the improvement, the health, the disease, the destruction, and the perfecting of other living things, has once and for all been placed within man’s reach by the discoveries of Darwin and Wallace.

Before Darwin—that is, before 1st July 1858—the origin of the different species of animals and plants was called by great thinkers like Sir John Herschel, the astronomer, “the mystery of mysteries.” The word “species” was defined as “an animal or plant which in a state of nature is distinguished by certain peculiarities of form, size, colour, or other circumstance from any other animal or plant, and propagates after its kind individuals perfectly resembling the parent, its peculiarities being therefore permanent.” So wrote a great naturalist in the days before Darwin. This definition may be illustrated by two common English birds—the rook and the crow. They differ from each other in slight peculiarities of form, structure, and habits, and, moreover, rooks always produce rooks, and crows always produce crows, and they do not interbreed. Therefore it was held that all the rooks in the world had descended from a single pair of rooks, and all the crows in like manner from a single pair of crows, while it was considered impossible that crows could have descended from rooks, or rooks from crows. The “origin” of the first pair of each kind was a mystery, and by many persons was held to have been due to a miraculous and sudden act of “creation.” But besides our crow and rook, there are about thirty other birds in various parts of the world so much like our crow and rook that they are commonly called crows, and are all regarded as “species” of the genus crow (or Corvus). It was held before Darwin that all the individuals of each of these “species” were descended from an ancestral pair of crows of that species. There would have been thirty different original kinds, the “origin” of which was unknown, and by naturalists was regarded as a mystery. Now, on the contrary, it is held that all the thirty living species are descended from one, not from thirty, ancestral species, and have been gradually modified to their present character in different parts of the world; and, further, that this ancestral species was itself derived by slow process of change and natural birth from preceding crow-like birds no longer existing.

As Mr. Alfred Russel Wallace has said in his most readable and delightful book, Darwinism—where he gives all the credit and glory to his great fellow-worker: “Darwin wrote for a generation which had not accepted evolution—a generation which poured contempt on those who upheld the derivation of species from species by any natural law of descent. He did his work so well that ‘descent with modification’ is now universally accepted as the order of nature in the organic world, and the rising generation of naturalists can hardly realise the novelty of this idea, or that their fathers considered it a scientific heresy to be condemned rather than seriously discussed.”

For those who are not naturalists or men of science it is an object-lesson of the highest importance, that the speculations and observations which have led to the general acceptance of a new view as to the origin of the species of birds, butterflies, and flowers—in itself apparently a matter of no consequence to human life and progress—should have necessarily led to a new epoch in philosophy, and in the higher state-craft; in fact, to the establishment of the scientific knowledge of life as the one sure guide and determining factor of civilisation. How to breed a healthy, capable race of men, how to preserve such a race, how to educate and to train it, so that its best qualities of mind and body may be brought to activity and perfection—this is what Darwinism can teach us, and will teach us when the great subjects of inheritance and of variation are more fully investigated by the aid of public funds, and when the human mind has been as carefully examined and its laws as well ascertained, as are those of the human body. There is no reason for delay; no excuse for it. For two thousand years the learned men of Europe debated as to whether this or that place was the site of ancient Troy, or whether there ever was such a place at all. At last (only twenty-five years ago) a retired man of business, named Schliemann, had a “happy thought”—it was not the thought of a learned pedant, but of a scientific investigator. He said, “Let us go and see.” And at the expense of a few thousand pounds he went and found Troy and Mycenæ, and revealed—“dis-covered”—the whole matter. That was the most tremendous and picturesque triumph of the scientific method over mere talk and pretended historical learning which has ever been seen since human record has existed. It ought to be told to every boy and girl, for it is the greatest and most obvious proof of the overwhelming power of the investigation of tangible things and the futility of chatter, which has ever been seen. It is enough to inspire hope and belief in experiment even in the breast of a Member of Parliament, or of a Minister of the Crown.

IV DARWIN’S DISCOVERIES

IV DARWIN’S DISCOVERIES

A large proportion of the public are not aware of the amount of experiment and observation carried out by the great naturalist whose memory was honoured by a splendid ceremony at the University of Cambridge in the summer of 1909. There are, I am sure, not a few who are under the impression that Darwin, sitting in his study or walking round his garden, had “a happy thought,” namely, that man is only a modified and improved monkey, and proceeded to write an argumentative essay, setting forth the conclusion that mankind are the descendants of some remote ancestral apes. Of course there is an increasing number of more careful and inquiring men and women who take advantage of the small price at which Mr. Darwin’s wonderful book, The Origin of Species, is now to be bought, and have read that and some of his other writings, and accordingly know how far he was from being the hasty and fanciful theorist they previously imagined him to be. It is the great distinction of Darwin that he spent more than twenty years of his life in accumulating the records of an enormous series of facts and observations tending to show that the species or “kinds” of animals and plants in nature can and do change slowly, and that there is, owing to the fact that every pair produces a great number of offspring (sometimes many thousand), of which only a single pair, on the average, survive, a necessary selection of those which are to survive and breed, accompanied by a rejection and destruction of the rest. This “natural selection” or survival of favoured varieties, he was able to show, must operate like the selection made by breeders, fanciers, and horticulturists, and has in all probability (for in a history extending over hundreds of thousands of years we must necessarily deal with “probabilities,” and not with direct demonstration) produced new forms, new kinds, better adapted to their surroundings than the parental forms from which they are derived.

It was necessary, in order that Darwin should persuade other naturalists that his views were correct, that he should show by putting examples “on the table” that variations occur naturally and in great diversity; further, that there is great pressure in the conditions of life, and a consequent survival of the best-suited varieties; further, that there is in reproduction a transmission of the peculiar favouring character or quality which enables a variety to survive, and thus a tendency to perpetuate the new quality. It was not enough for Darwin to “imagine” that these things might be so, or to make the notion that they are so plausible by arguments drawn from existing knowledge. He had to do that: but also he had to make new inquiries and discover new things about animals and plants which fitted in with his theory and would not fit in either with the notion that all plants and animals were created—as the poet Milton supposed—out of lumps of earth and muddy water, suddenly, in the likeness of their present-day descendants, nor with some other notions, such as that of the able and gifted French naturalist Lamarck. And he spent the later twenty years of his life in doing so, just as he had spent the previous twenty years in collecting a first series of facts and observations justifying his theory before he announced it to the world.

A great difference between Lamarck and Darwin exists, not only in their two theories as to the mode of origin of the vast diversified series of kinds or species of plants and animals, but in their way of stating and dealing with the theory which each thought out and gave to the world. Lamarck had a great knowledge of the species of plants and animals, partly through having collected specimens himself when he was an officer in the French Republican army which was employed on the Mediterranean shores of France and Italy more than a hundred years ago, and partly through his later official position in the great natural history museum at Paris, where large collections passed through his hands. He was a man of very keen insight and excellent method, and did more to plan out a natural and satisfactory “classification” of animals than any one between his own day and that of Linnæus. His theory of the origin of species was essentially an opposition to the then popular view that the species of living things have been made by the Creator so as to fit the conditions in which they live. Lamarck contradicted this view, and said in so many words that the real fact is that the peculiar specific characters of animals or of plants have not been created for their conditions, but, on the contrary, that the conditions in which they live have created the peculiarities of living things. In so far his conception was the same as Darwin’s. But Lamarck then said to himself: How do the conditions create the peculiarities of different living things? And he answered this question by an ingenious guess, which he published to the world in a book called Philosophical Zoology, without taking any steps to test the truth of his guess.

That is where Lamarck’s method and attitude as a scientific man is so greatly inferior to that of Darwin. Lamarck, sitting in his study, said animals (and plants too) must be affected by the conditions around them, so that an individual as it lives and grows becomes to a certain degree slightly changed by and adapted to those conditions. This, he said, we all see in human beings and familiar animals and plants. Now, he said, we have only to admit that the changes so acquired are (especially when both parents have been similarly changed) transmitted to the young in the process of generation, and to some degree “intensified,” in order to recognise that of necessity there is in nature a constant change and progression of living forms, consisting in a more and more elaborate “adaptation” to the conditions of life, which will be varied and lead to new adaptations as the living things spread over the earth or as geological changes occur. He cited the long neck of the giraffe as an example of what he meant. In regions where there was frequent and extensive drought, a deer-like creature would eat the lower leaves of trees when the grass was dried up and dead. It would strain and stretch its neck in reaching after the higher leaves, and the individuals thus straining and stretching would become an inch or two longer in the neck in consequence. These individuals would, said Lamarck, transmit their increased length of neck to their offspring, who again would strain and stretch after higher leaves, and get a further increase of neck-length, and so it would go on, little by little, over many thousand generations, until the neck-stretchers had become well marked and distinguished by their long necks from such of their ancestral stock as survived in other regions where, the grass being good, there was no inducement to straining and stretching the neck.

Now the great difference between Lamarck and Darwin is that Lamarck was quite content to state the ingenious supposition illustrated by the imaginary history of the giraffe, and to declare that this was the law of Nature and is actually going on every day, without, so to speak, getting out of his chair. He never attempted to show by observation or experiment that such a change of form as the stretching of the neck by straining after food could and did occur, or that if it did that it could be transmitted by a parent or couple of parents to their offspring. And consequently for many years no one attached much value to Lamarck’s notions on the subject. When, fifty years later, Darwin’s very different theory became widely received, based on the demonstrable fact that congenital variations (not stretchings and warpings acquired in the lifetime of a parent, but variations which are inborn, and occur in some but not other individuals living under one and the same set of conditions) are transmitted to offspring, and that those among these variations which are favourable to success in life will enable their possessor to survive and to produce young inheriting those favourable variations—then it occurred to those naturalists who were inclined to believe in Lamarck’s suggestion to inquire into the solid facts in regard to that also, and to see whether his bare statement was true. From that day to this, it has never been shown that it is true. It is, indeed, to begin with, a rare thing to find instances of either wild animals or wild plants which, growing up in unusual conditions, have their structure altered and “adapted” so as to be more serviceable in those unusual conditions than their usual structure would be; and in those cases where such adaptive alterations have been produced, every experimenter is agreed in stating that he has found that when (even after several generations in the changed conditions) the young are restored to their original conditions, they simply grow up into the original forms: no permanent change in the stock or race has been effected. Every attempt to show by experiment that a new character can be acquired by the stock in this way, and show itself by heredity alone—when the modifying adapting conditions are removed—has completely failed.

On the other hand, Darwin himself and his followers have made almost endless experiments and observations on plants and animals, establishing facts as to structure and the relation of special kinds of living things to their surroundings which can only be explained on the supposition that Darwin’s theory is true in detail; that is to say, not merely that the kinds of animals and plants have arisen from previous kinds by natural descent—that supposition is much older than either Darwin or Lamarck—but that the method by which the transformation has been brought about is ( a) the occurrence in every generation of every animal and plant of minute variations in every, or nearly every, part, and ( b) the continual selection in the severe struggle for existence of those individuals to grow to maturity and reproduce, which happen to present favourable variations, which variations are accordingly transmitted to the next generation, and may be intensified, so far as intensification is of value, in each succeeding generation.

A book full of observations and reflections about the structure, habits, and mode of occurrence and geography of a great number of plants and animals is Darwin’s Journal of Researches, published in 1845, and now republished as A Naturalist’s Voyage. In order to know very minutely the differences and resemblances between all the kinds or species of one group of living things Darwin studied for eight years the “cirrhipedes,” the name given to the sea-acorns and ships’ barnacles which occur in all parts of the world, some living on rocks, some on the backs of turtles, others on whales, on the feet of birds, on bits of floating wood or of pumice-stone, and some on one another! They are all hermaphrodites, but Darwin found in several a most singular thing, namely, the existence of minute males, complemental to and parasitic on the hermaphrodites. His discovery was doubted and denied, but he had the pleasure of seeing it at last fully confirmed thirty years after his book on cirrhipedes was published.

Darwin discovered that the presence of the same species of plants and of some few animals on distant mountain summits and in the Arctic region is due to the former extension of ice between these situations during the last glacial period. He was, before everything else and by necessity for the examination of his theory, a geologist, and wrote many valuable geological memoirs. The history of the origin of the species of living things consists largely in tracing them to extinct creatures, and in showing what were the possible migrations and what the conditions of land and water, temperature and vegetation, in past periods, and in regard to given areas of the globe. The book on the Fertilisation of Orchids was the first published by Darwin after the Origin of Species. In it he showed how the marvellous shapes and colours and mechanisms of the flowers of orchids are adapted to ensure cross-fertilisation by insects, and how they can be explained as originating by the natural selection of variations—if the value of cross-fertilisation is once recognised. The explanation of the reason for the existence of two kinds of primrose flowers—the short-styled and the long-styled—clearly arrived at by him as being a mechanism to secure cross-fertilisation, delighted him in 1862, and led him to discover the same sort of modification in other flowers. Then, in 1864, he published his researches on Climbing Plants, and later a book on the Movements of Plants, in which he discovered the mechanism and the wonderful variety of movements of plants, and showed their value to the plant, and consequent origin, by natural selection.

He especially loved to discover evidence that plants can do many things which had been thought to be only within the powers of the other section of living things—the animals; and finding during one summer holiday that the beautiful little sun-dew moves its red-knobbed tentacles so as to entrap minute insects, he discovered the whole history of Insectivorous Plants, and showed that there are many plants of various groups which catch insects and digest them in a sort of stomach, as an animal might do. Thus the water-holding pitchers of the pitcher-plants of tropical forests were explained as being food-catchers and digesters of great value to the nutrition of the plant, and their gradual formation by variation and natural selection rendered comprehensible.

His greatest book next to the Origin—containing an immense quantity of original notes and observations and valuable information from all kinds of breeders and fanciers—is the Variation of Animals and Plants under Domestication (1868). The facts recorded are discussed in the light of the great theory, and honest, fair-minded consideration is given to those which present difficulties as well as to those which clearly favour it. In 1871 came the Descent of Man, followed in 1872 by the Expression of the Emotions in Men and Animals—in which, again, it was shown that the facts as to the likeness between man and apes can be explained on the theory that natural selection and survival of favourable variations have been at work, and that the facts are hopelessly without meaning or explanation on any other hypothesis. His last published book was on The Formation of Vegetable Mould through the Action of Worms, in which he not only showed what an important part earthworms play in burying stones and rocks, and in fitting the ground for the growth of plants, but recorded some discoveries as to the senses of worms and as to their treatment of leaves by a digestive fluid exuded from the mouth so as to soften a leaf before swallowing it.

Every one of Darwin’s books abounds with new facts and new points of view disclosed by the application to first one thing and then another of his vivifying discovery-causing theory of natural selection. The subsidiary theory of the selection of brilliantly coloured males by females in pairing, as a cause of the brilliant colours and patterns of many birds and insects, is developed in his Descent of Man. It led him to many important discoveries and observations as to the colouring and ornamentation of animals, and when considered, together with Wallace’s and Bates’s theory of mimicry and of the warning and protective colourings of insects, goes far to explain all the specific colouring of animals and plants as due to natural selection and survival. A theory which has produced such prodigious results in the way of “explaining” all forms, colours, habits, and occurrences of living things—as has that of Charles Darwin—simply holds the field against all comers. When Lamarck’s theory has been shown to be consistent with the most elementary facts as to heredity, and further to afford a rational explanation of any group of biological facts, it will be time to consider how far it may be entertained in conjunction with Darwin’s theory—but not until then.

V DARWIN’S THEORY UNSHAKEN

V DARWIN’S THEORY UNSHAKEN

It seems ill-mannered, if not ill-natured, that the year of the centenary of Charles Darwin’s birth should have been chosen by owners of anonymous pens in order to alarm the public mind with the preposterous statement that his celebrated and universally accepted theory of the origin of the species or kinds of plants and animals by natural selection, or “the survival of favoured races in the struggle for life,” is undermined and discredited. Such a statement once coolly made in the public Press is necessarily believed by a large number of uninformed readers, and, like all calumny, is none the less relished by the foolish, and, for the moment, none the less harmful, because it is baseless.

Those who seek to belittle Darwin’s theory show, whenever they venture to enter into particulars, that they do not know what Darwin’s theory is. They confuse it with other theories, and even imagine that some enthusiastic Darwinians who have tried to add a chapter here or there to Darwin’s doctrine, are opponents of the great theory. Let me briefly state what that theory is:

It rests on three groups of facts—matters of observation, which are not theory or guess work at all—but admitted by every one and demonstrated every day. These are—(1) Living things, each in its kind, produce a far larger number of young than can possibly grow up to maturity, since the kind of food and the situation necessary to each kind are limited and already occupied. Only one oyster embryo out of every five million produced (the reader may refer to p. 137 on this subject) grows up through all the successive stages of youth to the adult state. The total number of a species of animal or plant on the whole area where it is found does not increase. Even in those which produce a small number of young, there is great destruction, and taking all the individuals into consideration, only a single pair of young arrive at maturity to replace their parents. There is no exception to the rule that every organic being naturally multiplies at so high a rate that, if not destroyed, the progeny of a single pair would soon cover the earth. The elephant is reckoned the slowest breeder of known animals; it commences to breed at 30 years of age, dies at 100, and has six young in the interval. After 750 years, supposing all the offspring of a single pair fulfilled the rule and were not destroyed in an untimely way, there would be nearly nineteen million elephants alive descended from the first pair. There is then no doubt as to the enormous excess in the production of young living things, nor as to their necessary competition with one another of the most severe and inexorable kind; nor again as to the necessary death, in many species, of hundreds and thousands, for every one which survives to maturity and in its turn breeds.

(2) The second great fact is that among all the young born to a pair of parents, no two are exactly alike, nor are any exactly like their parents; nor are any two taken from all produced by all parents of that species exactly alike. They all resemble their parents at the corresponding age, in a general way and even very closely; but the resemblance is far from amounting to identity. This is called “variation.” It is familiar to us all in the case of the organism which we know best, and observe most closely, namely, man. It is also a matter of common observation in the case of dogs, cats, horses, and other domesticated animals. Many of these “variations” are exhibited in points of size, proportion, and colour, which are easily noted at once by the eye. But “variation” is really a deep-seated thing, and depends on causes which lie below the surface. We know that the offspring of men and of animals and of plants, give evidence of variations in what we call constitution, tendency, temperament, aptitude, strength, and that the colour, and even size of this or that part, are really only indications of a deep-seated difference in the living chemistry, the forces of nutrition and growth which reside in the living substance. The fact that many thousands of a species may be born and only a few survive, means therefore that many thousand varieties, often varieties not readily measured by the eye, are produced in each generation, from which a few individuals are in some way “selected” for survival.

(3) The third great fact is that though there is variation, amongst all the offspring in each generation, there is also a continual and definite inheritance by offspring of the qualities and structure of their parents to a degree which altogether preponderates over the variations. To put it in another way, we all know that every parental organism transmits to its young not only the qualities and structure of the species, or of the race, or of the family, but also transmits its own peculiarities or variations in which it departed from its parents, and from its brothers and sisters. This is best illustrated by our daily experience of human families.

These facts being admitted, and abundantly illustrated and traced in detail by years of observation and experimental breeding in all kinds of living things by hundreds of careful observers who have published the records of their studies, we come to the step where Darwin makes use of supposition or hypothesis. The question is, “Does the one which, out of the thousands of slightly different varieties, survives—do so by haphazard? or is there a necessarily acting state of things which selects that one special variety for survival?” Gardeners and breeders of pigeons, dogs, and cattle deliberately select the variations which they desire, breed from them, and so carry on by inheritance the special variation—whilst they ruthlessly destroy or restrain from breeding the numerous other variations in their “stock” which they do not desire. “If,” said Darwin, “there is any necessarily selective mechanism in Nature which could act as the breeder does, new varieties might be ‘naturally’ selected, and changes of form and appearance naturally established, which in the course of long ages would amount to such marked differences as separate what we call one species from another.” He showed that there is a natural mechanism of the required kind. “Since,” he says, “the competition among the members of any one kind or species for a place in life is so very severe, and the hostile circumstances so varied, and since all the competing offspring differ by ‘variation’ ever so little from one another, those varieties which are better suited in even the smallest degree to hold their own not merely in fighting with the others, but in withstanding injurious influences, in escaping enemies, and in procuring food, will be the ones which will survive, when a large number of cases, many thousands, extending over a large area and many years, are considered. Those which are ‘best fitted’ to get through the exceedingly numerous dangers and difficulties of life will be the survivors.” Hence we get the survival of the fit—the fit variations—by natural selection in the struggle for life. This, it will be observed, is an inference, and not a direct observation.

So long as the conditions remain practically or effectively unchanged, the animal or plant already “fitted” to them will be succeeded by those of its offspring which most resemble it in the essential points of “fitness.” But we know that in the course of ages, more or less rapidly, climates change, land emerges from the sea, islands join continents, continents become scattered islands, animals and plants migrate into regions previously uninhabited by them. As such changes gradually come on, the natural selection of favoured varieties will necessarily lead to the survival of others than those previously favoured, other variations better suited to the new conditions will survive.

The natural selection of favoured variations would not amount to much, were the variations not perpetuated by transmission to the young which they produce. This, it is common knowledge [see (3)], does take place. It is known also that a variation so established is as a result of the regular process of variation presented in larger volume or emphasised in character in some individuals of subsequent generations, and by continued “natural selection” it may become more and more a prominent or dominant feature of the race.

So far, the only assumption made by Mr. Darwin is that any or some of the endless variations which occur in all the offspring of wild plants and animals, in various combinations and degree in each individual, can be sufficiently important to determine the survival or non-survival of the organisms possessing them. That is a matter which has been largely studied and discussed. The verdict of those who have studied on the spot (as Darwin himself did) the teeming life of the tropics, the insects, birds, and plants of those regions, is that we are justified in considering that small variations are sufficiently important to turn the scale in favour of survival or non-survival. It is not easy for a man who is not a determined naturalist, constantly observing the ways of wild living things, to appreciate the evidence as to the efficacy of small variations, even were I able here to submit it to him. It is to be found in the published works of an army of investigators. In any case it is granted that effective variations—whether small or great—occur in nature, and that natural selection favours and perpetuates the new and fitter variety to the exclusion of the less fit.

The real difficulty to most people comes in the supposition next made by Mr. Darwin—namely, that this slow process of change by natural selection of favoured variations and their transmission and perpetuation by inheritance is sufficient to effect by its continued operation through enormous ages of time the conversion of a race of ancestral three-toed zebras into the one-toed horse of to-day; before that, of five-toed beasts into three-toed; at an earlier stage of fishlike creatures into four-footed land animals, and so on. You have to picture the whole series of animals and of plants which are now or ever have been, as two gigantic family trees or pedigrees, meeting in common ancestors of the simplest grade of microscopic life. All the diverging branches and twigs of these great “family trees” have been determined by the adaptation of living form to the endlessly varied conditions of life on this planet, by the natural selection or survival of variations and the transmission and accumulation of those variations from parent to offspring. This is a tremendous demand on the imagination. It is, however, not a difficult one to concede, when one is acquainted with the facts and conclusions of geology. The history of the crust of the earth was explained twenty years before the date of Darwin’s theory by Charles Lyell as due to the continued action through immense periods of time of the same natural forces which are now at work. And, moreover, the examination of the successive stratified deposits of the earth’s crust has yielded the remains of whole series of animals and of plants (simpler in character the older and deeper the rock in which they occur), which can be satisfactorily explained and interpreted as the ancestral forms from which present organisms have been developed.

The theory of the natural selection of variations as the moving spring in the gradual development of living forms from simplest living matter is Darwin’s theory. It is not possible to find any naturalist of consideration who does not accept it. There are various views held and discussed as to the cause of variation, as to the importance of small and of big variations, as to the non-transmissibility of some kinds of variation, and as to various peculiarities in regard to inheritance. They do not for the most part touch the main features of Mr. Darwin’s theory. No doubt we are learning and shall learn more about the facts of variation and the details of the process of hereditary transmission, but such increase of knowledge has not tended to undermine Mr. Darwin’s theory, and does not seem at all likely to do so.

On the occasion of the celebration at Cambridge in 1909 of the centenary of Darwin’s birth, I was invited by the Vice-Chancellor, on behalf of the University, to deliver in the Senate-house an address, others being given by representatives of the United States (Prof. Osborne), of Germany (Prof. Hertwig), and of Russia (Prof. Metchnikoff). The following is the text of that address:—

“I feel it a great honour to be called upon to speak here to-day, and to stand, on behalf of the naturalists of the British Empire, by the side of the distinguished men whose orations you have just heard.

“I think that the one thing about Charles Darwin which the large majority of British naturalists would wish to be to-day proclaimed, in the first place—with no doubtful or qualifying phrase—is that, in their judgment, after these fifty years of examination and testing, his ‘theory of the origin of species by means of natural selection or the preservation of favoured races in the struggle for life’ remains whole and sound and convincing, in spite of every attempt to upset it.

“I am not stating more than the simple truth when I say that, in the judgment of those who are best acquainted with living things in their actual living surroundings, ‘natural selection’ retains the position which Mr. Darwin claimed for it of being the main means of the modification of organic forms.

“Our admiration for the vast series of beautiful observations and interesting inquiries carried out by Darwin during his long life must not lead us to forget that they were devised by him in order to test the truth of his theory and to meet objections to it, and that they were triumphantly successful. They, together with the work of Alfred Russel Wallace and many of their followers, have more and more firmly established Darwin’s theory. On the other hand, no attempt to amend that theory in any essential particular has been successful.

“The nature of organic variation and of the character of the variations upon which natural selection can and does act was not, as we are sometimes asked to believe, neglected or misapprehended by Darwin. The notion that these variations are large and sudden was considered by him, and for reasons set forth by him at considerable length rejected. That notion has in recent years been resuscitated, but its truth has not been rendered probable by evidence either of such an accurate character or of such pertinence as would justify the rejection of Darwin’s fundamental conception of the importance of minute and ubiquitous variations.

“Further, in regard to the important facts of heredity connected with the cross-breeding of cultivated varieties, especially in regard to the blending or non-blending of their characters in their offspring and as to prepotency, it seems to me important that we should now and here call to mind the full and careful consideration given to this subject by Darwin. We cannot doubt that he would have been deeply interested in the numerical and statistical results associated with the name of Mendel. Those results tend to throw light on the mechanisms concerned in hereditary transmission, but it cannot be shown that they are opposed in any way to the truth of Darwin’s great theoretical structure—his doctrine of the origin of species.

“It has often been urged against Darwin that he did not explain the origin of variation, and especially that he has not shown how variations of sufficient moment to be selected for preservation in the struggle for existence have in the first place originated. The brief reply to the first objection is that variation is a common attribute of many natural substances of which living matter is only one. In regard to the second point, I desire to remind this assembly that Darwin described with special emphasis instances of what he calls ‘correlated variability.’ In my opinion he has thus furnished the key to the explanation of what are called useless specific characters and of incipient organs. That key consists in the fact that a general physiological property or character of utility is often selected and perpetuated, which carries with it distinct, even remote, correlated growths and peculiarities obvious to our eyes, yet having no functional value. At a later stage in the history of such a form these correlated growths may acquire value and become the subject of selection.

“It is thus, as it seems to me, and as, I believe, to the great body of my brother naturalists, that Darwin’s theory stands after fifty years of trial and application.

“The greatness of Charles Darwin’s work is, and will be for ever, one of the glories of the University of Cambridge. It is fitting on the present occasion that one who speaks on behalf of English men of science should call to mind the nature of his connection with this great University and the peculiarly English features of his life-story and of that fine character which endears his memory to all of us as much as his genius excites our admiration and reverence. Darwin was not, like so many a distinguished son of Cambridge, a scholar or a fellow of his college, nor a professor of the University. His connection with the University and the influence which it had upon his life belong to a tradition and a system which have survived longer in our old English universities than in those of other lands. Darwin entered the University, not seeking a special course of study with the view of professional training, nor aiming at success in competitive examinations for honours and emolument. He came to Cambridge intending to become a clergyman, but blessed with sufficient means and leisure to enable him to pursue his own devices, to collect beetles, to explore the fen country, and to cultivate his love of nature. It was thus that he became acquainted with that rare spirit Henslow, the Cambridge professor of botany, and it is through Henslow and the influence of his splendid abilities and high personal character upon Darwin that Cambridge acquired the right to claim the author of the ‘Origin of Species’ as a product of her beneficence and activity as a seat of learning.

“As an Oxford man and a member of Exeter College, I may remind this assembly that in precisely the same way Darwin’s dearest friend and elder brother in science, Charles Lyell, had a few years earlier entered at Exeter College, and by happy chance fallen under the influence of the enthusiastic Buckland, the University reader in geology and a Canon of Christ Church. The wise freedom of study permitted and provided for in those long-passed days by Oxford and Cambridge is what has given the right to claim the discovery, if not the making, of Lyell to the one and of Darwin to the other.

“Darwin’s love of living nature and of the country life are especially English characteristics; so, too, I venture to think, are the unflinching determination and simple courage—I may even say the audacity—with which he acquired, after he had left the University, the wide range of detailed knowledge in various branches of science which he found necessary in order to deal with the problem of the origin of the species of plants and animals, the investigation of which became his passion.

“The unselfish generosity and delicacy of feeling which marked Darwin’s relations with a younger naturalist, Alfred Russel Wallace, are known to all. I cannot let this occasion pass without citing those words of his which tell us most clearly what manner of man he was and add to his splendid achievements as an intellectual force—a light and a beauty of which every Englishman must be proud. When in old age he surveyed his life’s work he wrote:—‘I believe that I have acted rightly in steadily following and devoting my life to science.’