Part 5

On this centenary when we are honoring Darwin, many may ask, exactly what is Darwinism? Failure to know leads some to doubt, others to predict a decline, especially where “the wish is father to the thought.” Nothing could be less true than to say that there is the least abatement in the force of the main teaching of this great leader, namely, of the evolutionary law of the universe. The vitality of this idea is shown by its invasion of the physical world. Again, Darwinism is the sum of Darwin’s observations on earth structure, on plants, animals and man. This vast body of truth and of interpretation still so far surpasses that brought forward by any other observer of nature, and these facts and interpretations are so far confirmed that they have become the very foundation-stones of modern biology and geology. Finally, looking at Darwinism as the sum of his generalizations as to the processes of evolution we again find a vast body of well-established laws which are also daily becoming more evident. As to the laws of evolution, there is no single biological principle more absolutely proved by the study of living and extinct things since Darwin’s time than the broad law of natural selection: certainly the fittest survive and reproduce their kind, the fittest of every degree, all classes, orders, genera, species, individuals and even the fittest organs and fittest separate parts of organs. Darwin still gives us the only explanation which has ever been suggested of hundreds of thousands of adaptations of which neither Buffon’s view of direct effect of environment nor Lamarck’s view of the inheritance of bodily modifications even approaches an explanation worthy to be considered. Take the egg of the murre or guillemot, which is so much larger at one end than the other that it cannot roll off the cliff on which it is laid, or the seasonal changes of color in the ptarmigan, every one of which is protective.

There is some lack of perspective, some egotism, much one-sidedness in modern criticism. The very announcement, “Darwin deposed,” attracts such attention as would the notice “Mt. Blanc removed”; does it not bespeak courage to attack a lion even when deceased? Preoccupation in the study of one great law, as in the case of Bateson on Mendelism and De Vries on Mutation, blinds to every other law. To be dispassionate, let us remember that Darwin’s hypothesis was framed in 1838, seventy-one years ago. Are the two great Cambridge men, Newton and Darwin, lesser men because astronomy and biology are progressive sciences? Secondly, to know your Darwin you must not judge him by single passages but by all he wrote. Darwin is not to be known through the extremes of those of his followers with whom an hypothesis has become a creed. Reading him afresh and through and through we discover that his “variation” and “variability” are very broad and elastic terms. Every actual example he cites of his main hypothesis, such as the speed of the wolf or the deer, or the long neck of the giraffe, is a variation both heritable and of adaptive value.

When we put together all the concrete cases which he gave to illustrate his views of selection we see that he includes both continuous and discontinuous variations, both the shades of difference of kind and proportion and the little leaps or saltations from character to character. For example, certain cases of immunity to disease are now known to be “unit characters” in Bateson’s sense, or “mutants” in the De Vries sense. Darwin repeatedly referred to immunity as a variation which would be preserved by selection. Moreover, Darwin’s own repeated assertion of his profound ignorance of the laws of variation certainly pointed the way to the investigation of these laws, and it is this very study which is modifying the applications of his selection hypothesis.

From first to last Huxley maintained that it would require many years of study before naturalists could say whether Darwin had been led to overestimate the power of natural selection. Darwin’s mind from first to last was also open on this point. Through every edition of the “Origin” we find the passage:

The laws governing the incipient or primordial variations (unimportant except as the groundwork for selection to act on and then all important) I shall discuss under several heads. But I can come, as you may well believe, to only very partial and imperfect conclusions.

In 1869 and in the latest edition of the “Origin” Darwin speaks of “individual differences” as of paramount importance, but he illustrates these differences by such instances as the selection of passenger pigeons with more powerful wings, or the selection of the lightest colored birds in deserts.

There can be no question, however, that Darwin did love his selection theory and somewhat overestimated its importance. His conception of selection in nature may be compared to a series of concentric circles constantly narrowing from the largest groups down to the minutest structures. In the operations of this intimate circle of minute variations within organisms he was inclined to believe two things: first, that the fit or adaptive always arises out of the accidental, or that out of large and minute variations _without direction_ selection brings direction and fitness; second, as a consistent pupil of Lyell, he was inclined to believe that the chief changes in evolution are slow and continuous.

The psychology of Darwin was in a reaction state from the prevailing false teleology; he was not expecting that purposive or teleological or even orthogenetic laws of variation would be discovered. William James has thus recently expressed and endorsed the spirit of Darwinism as a new natural philosophy in the following words:

It is strange, considering how unanimously our ancestors felt the force of this argument [that is, the teleological], to see how little it counts for since the triumph of the Darwinian theory. Darwin opened our minds to the power of the chance-happenings to bring forth “fit” results if only they have time to add themselves together. He showed the enormous waste of nature in producing results that get destroyed because of their unfitness.

The question before us naturalists today is whether this non-teleological spirit of Darwinism as expressed by William James corresponds with the actual order of evolution in nature. This really involves the deep-seated query whether the intimate or minute parts of living things are operating under natural laws like non-living things or are really lawless.

Before expressing my individual opinion based on my own researches of the last twenty years I may summarize the general modern dissent: in _three points_ it may be said that Darwin’s teachings are not accepted today.

First, his slowly developed belief in the inheritance of bodily modifications and the provisional “assemblage theory” of heredity which he called _pangenesis_ has been set aside for Weismann’s law that heredity lies in the continuity of a specific heredity plasm, and for want of evidence of the transmission of acquired characters.

Second, while his prevailing belief that changes in organisms are in the main slow and continuous is now positively demonstrated to be correct by the study of descent in fossil organisms, there is also positive evidence for the belief which he less strongly entertained that many changes are discontinuous or mutative, as held by Bateson and De Vries.

Finally, his belief that out of fortuitous or undirected variations in minute characters arise direction, purpose and adaptation through selection still lacks proof by either observation or experiment. Fossil and other descent series entirely unknown in Darwin’s time prove beyond question that law rather than chance is prevailing in variation.

What the nature of these laws is it is still too early to say. Personally I am strongly of the opinion that the laws of life, like the ultimate laws of physics, may eventually prove to be beyond analysis.

To allow myself just one flight of fanciful statement drawn from personal observation and reflection I may say there is a likeness between the unit forces working in a single organism, both as revealed by the microscope and in fossil series, and the individual soldiers composing a giant army. The millions of well-ordered activities in the body correspond with the millions of intelligently trained men who compose the army; the selection process or the survival of the fittest is like the competition between two armies, between the Russian and Japanese, for example. It is an outward and visible competition between two internally prepared and well-ordered hosts of units and groups of units. Selection is continuously working upon the army as a whole and also upon every unit which affects survival—an immunity unit, an intelligence unit, a speed unit, a color or group of color units; just as in the army it is working upon units of courage, of strategy, of precision of fire, of endurance, of mass. In this sense it is perfectly true to say with Darwin “that selection works upon certain single variations.” It is not true, or at least it is not shown, that these variations are a matter of chance; they rather appear to be a matter of law, as indeed Darwin foresaw when he stated that he used the word “chance” merely as a synonym of “ignorance.”

In the present state of biology we are studying the behavior of the thousands of parts, sometimes of blending, sometimes of separate, sometimes of paired or triplicate units, which compose the whole and make up the individual organism. Natural selection determines which organism shall win; more than this, it determines which serviceable activities of each organism shall win. Here lie the limits of its power. Selection is not a creative but a judicial principle. It is one of Darwin’s many triumphs that he positively demonstrated that this judicial principle is one of the great factors of evolution. Then he clearly set our task before us in pointing out that the _unknown_ lies in the laws of variation, and a stupendous task it is. At the same time he left us a legacy in his inductive and experimental methods by which we may blaze our trail.

Therefore, in this anniversary year, we do not see any decline in the force of Darwinism but rather a renewed stimulus to progressive search. As Huxley says:

But this one thing is perfectly certain—that is, it is only by pursuing his method, by that wonderful single-mindedness, devotion to truth, readiness to sacrifice all things for the advance of definite knowledge, that we can hope to come any nearer than we are at present to the truths which he struggled to attain.

THE DARWIN CENTENARY AT CAMBRIDGE

Crossing the Atlantic in honor of Darwin and rejoicing in the privilege of uniting in this celebration of his birth, we desire, first of all, to render our tribute to the University of Cambridge....

What can we add to the chorus of appreciation of the great pupil of Christ’s which has come from college, press and pulpit since the opening of this anniversary year? Only a few words of _personal impression_.

To us, Darwin, more perhaps than any other naturalist, seems greatest in the union of a high order of genius with rare simplicity and transparency of thought. Dwelling on this lucid quality and on the vast range of his observation from the most minute to the grandest relations in nature, does not the image arise of a perfected optical instrument in which all personal equation, aberration and refraction are eliminated and through which, as it were, we gaze with a new vision into the marvellous forms and processes of the living world? With this wondrous lens our countrymen, Cope and Marsh, penetrated far deeper into fossil life than their predecessor Joseph Leidy, and the arid deserts of the Rocky Mountain region gave up their petrified dead as proofs of Darwinism. Through its new powers Hyatt, Morse, Packard and Brooks saw far more than their master Louis Agassiz and drew fresh testimonies of development from the historic waters of New England. From the very end of the new world, where the youthful Darwin received his first impressions of the mutability of the forms of life, we enjoy a clearer vision of the ancient life of Patagonia.

What of Darwin’s future influence?

While it is doubtful if human speculation about life can ever again be so tangential as in our pre-Darwinian past of fifty years ago, it is probable, in fact it is daily becoming more evident, that the destiny of speculation is less the tangent than the maze—the maze of innumerable lesser principles, with as many prophets calling to us to seek this turning or that. There are those who in loyal advocacy of his system feel that we shall not get much nearer to life than Darwin did, but this is to abandon his progressive leadership, for if ever a master defined the unknown and pointed the way of investigation, certainly it was Darwin. In the wonderful round of addresses in his honor of this Centennial Year and in the renewed critical study of his life and writings, the recognition that Darwin opened the way has come to many with the force of a fresh discovery. It is true that he left a system and that he loved it as his own, but his forceful, self-unsparing and suggestive criticism show that if he were living in these days of Waagen, of Weismann, of Mendel and of De Vries, he would be in the front line of inquiry, armed with matchless assemblage of fact, with experiment and verification, and not least with incomparable candor and good will. This bequest of a noble method is hardly less precious than the immortal content of the “Origin of Species” itself.

THOMAS HENRY HUXLEY 1825–1895

To the memory of Balfour and of Huxley, my chief teacher in comparative anatomy, I dedicated my work, “The Age of Mammals.” Huxley set forth the logic of Darwin as applied to palæontology. Only a few men of the last century had the gift of speaking in clear language both to the learned and unlearned, and the greatest of these was Huxley. To write both for the man of one’s own profession and for the layman, to be accurate and abreast of the specialist who knows a subject as well as or better than you do, while intelligible to the non-specialist—there is the difficulty. Many times have I thought how simple it would be to address either audience separately. Yet I consider it fortunate that both are with us, because I share Huxley’s confidence in addressing those who are willing to do a little serious thinking in order to enjoy the vast vistas of interesting truth which come as the reward of effort. I share also his conviction that it is the duty of the man of science to devote a certain part of his time, however absorbed in research he may be, to an honest attempt to scatter scientific truth.

During the winter of 1879–80 I attended Huxley’s full course of lectures on Comparative Anatomy and Evolution, which were delivered in the upper floor of the Royal College of Science. In “A Student’s Reminiscences of Huxley” I especially attempt to describe personal impressions which he made upon me as a lecturer and as a thinker and to record some of the flashes of wit with which he enlivened his lectures. Although intensely occupied at the time with a variety of public education matters and with the pressure of literary and scientific work, Huxley found time, chiefly in his home, to enter into conversation on the subjects flooding his mind. It was there that I heard some of the best stories here recorded.

A STUDENT’S REMINISCENCES OF HUXLEY

By far the larger number of American students who go abroad pass through the English Channel, obtain a distant view of the mother country and, after from one to three years in Germany, return with an exclusively German education. Neither England nor France having been visited, the implication is that the countries which produced Owen, Darwin, Huxley and Balfour, or Lamarck, Cuvier, St. Hilaire and Pasteur have nothing to offer the American student. This is not the fact; the fact is that England and France are a half-century behind Germany in that kind of university organization which attracts a foreign student and enables him immediately to find his level and enter upon his research. English and French universities until a very recent date either have been not so fully prepared or have met the newcomer with practically insuperable obstacles in the matter of a degree.

None the less, the student who has not breasted these obstacles for the compensating advantages which the English and French schools offer has made a serious mistake. He has brought back not an Old World education, but an exclusively German education, with its splendidly sound and unique features and with many inherent defects. Germany produces the generals and the rank and file of the armies of science, but certainly the commanders-in-chief, in biology at least, have been Englishmen. If we find the highest exponents of purely inductive research in Germany, we certainly find a better union of the inductive and deductive methods in France and England. France leads in expression and style of thought, although, upon the whole, less sound in substance than Germany. England and France in her best period have given us the most far-reaching and permanent generalizations in biology. It follows that the American student who can afford the experience will profit most by placing himself successively in the scientific atmosphere of Germany, France, and England. My own post-graduate education was unfortunately not of this three-sided type. None the less, it has always seemed a most fortunate circumstance that in the spring of 1879 a letter from the venerable Kitchen Parker led me to Cambridge and to the great privilege of sitting under Balfour, the most brilliant and lovable of men. In the following autumn Huxley’s lectures upon Comparative Zoology began in October, and by entering this course I came to know personally this great master and through him to enjoy the rare opportunity of meeting Charles Darwin. After this experience, which was equally open to any serious student of biology at that time, it is natural that I should strongly advise those of you who are planning your foreign studies to spend part of your time in England and endeavor to discern some of the distinctive qualities of English men of science which Huxley so nobly illustrated. You will pardon the personal element in the following recollections of Huxley as a teacher and the rather informal review of his life-work.

Huxley as a teacher can never be forgotten by any of his students. He entered his lecture-room promptly as the clock was striking nine, rather quickly and with his head bent forward “as if oppressive with its mind.” He usually glanced attention to his class of about ninety and began speaking before he reached his chair. He spoke between his lips, with perfectly clear analysis, with thorough interest, and with philosophic insight which was far above the average of his students. He used very few charts, but handled the chalk with great skill, sketching out the anatomy of an animal as if it were a transparent object. As in Darwin’s face, and as in Erasmus Darwin’s, Buffon’s, and many other anatomists with a strong sense of form, his eyes were heavily overhung by a projecting forehead and eyebrows and seemed at times to look inward. His lips were firm and closely set, with the expression of positiveness, and the other feature which most marked him was the very heavy mass of hair falling over his forehead, which he would frequently stroke or toss back. Occasionally he would lighten up the monotony of anatomical description by a bit of humor. I remember one instance which was probably reminiscent of his famous tilt with Bishop Wilberforce at the meeting of the British Association in 1860. Huxley was describing the mammalian heart and had just distinguished between the tricuspid valve, on the right side of the heart, and the bicuspid valve, on the left, which you know resembles a bishop’s mitre, and hence is known as the mitral valve. He said:

It is not easy to recall on which side these respective valves are found, but I recommend this rule: you can easily remember that the mitral is on the left, because a bishop is never known to be on the right.

Huxley was the father of modern laboratory instruction, but in 1879 he was so intensely engrossed with his own researches that he very seldom came through the laboratory, which was ably directed by T. Jeffrey Parker, assisted by G. B. Howes and W. Newton Parker, all of whom are now professors, Howes having succeeded to Huxley’s chair. Each visit therefore inspired a certain amount of terror, which was really unwarranted, for Huxley always spoke in the kindest tones to his students, although sometimes he could not resist making fun at their expense. There was an Irish student who sat in front of me, whose anatomical drawings in water-color were certainly most remarkable productions. Huxley, in turning over his drawing-book, paused at a large blur under which was carefully inscribed “sheep’s liver” and smilingly said: “I am glad to know that is a liver; it reminds me as much of Cologne Cathedral in a fog as of anything I have ever seen before.” Fortunately the nationality of the student enabled him to fully appreciate the humor.

The greatest event in the winter of 1879 was Darwin’s first and only visit to the laboratory. They came in together, Huxley leading slowly down the long, narrow room, pointing out the especial methods of teaching, which he had originated and which are now universally adopted in England and in this country. Darwin was instantly recognized by the class as he entered and sent a thrill of curiosity down the room, for no one present had ever seen him before. There was the widest possible contrast in the two faces. Darwin’s grayish-white hair and bushy eyebrows overshadowed a pair of deeply set blue eyes, which seemed to image his wonderfully calm and deep vision of nature and at the same time to emit benevolence. Huxley’s piercing black eyes and determined and resolute face were full of admiration and, at the same time, protection of his older friend. He said afterward: “You know, I have to take care of him; in fact, I have always been Darwin’s bulldog,” and this exactly expressed one of the many relations which existed so long between the two men.