Part 7

This is a red letter day for me. As I was leaning over my lobster (Homarus vulgaris) this morning, cutting away at the brain, I raised my head and looked up to see Huxley and Darwin passing by me. I believe I never shall see two such great naturalists together again. I went on apparently with skill, really hacking my brain away, and cast an occasional glance at the great old gray-haired man. I was startled, so unexpected was it, by Huxley speaking to me and introducing me to Darwin as “an American who has already done some good palæontological work on the other side of the water.” I gave Darwin’s hand a tremendous squeeze (for I never shall shake it again) and said, without intending, in an almost reverential tone, “I am very glad to meet you.” He stands much taller than Huxley, has a very ruddy face, with benevolent blue eyes and overhanging eyebrows. His beard is quite long and perfectly white and his hair falls partly over a low forehead. His features are not good. My general impression of his face is very pleasant. He smiled broadly, said something about a hope that Marsh with his students would not be hindered in his work, and Huxley, saying “I must not let you talk too much,” hurried him on into the next room.

I may add, as distinctly recorded in my memory, that the impression of Darwin’s bluish-gray eyes, deep-set under the overhanging brows, was that they were the eyes of a man who could survey all nature.

Another memory of interest is that the instant Huxley closed the door I was mobbed as the “lucky American” by the ninety less fortunate students of Great Britain and other countries.

Huxley’s solicitude for Darwin’s strength was characteristic of him. He often alluded to himself as “Darwin’s bull dog.”

I have already stated that of the two men Darwin gave the impression of enjoying the better health. Huxley was then sixteen years the younger, yet the burdens and strain of London life made him look less young and hale. In this connection an earlier jotting from the same laboratory is as follows:

Huxley comes in as the clock strikes and begins to lecture at once, almost before it ceases. He looks old and somewhat broken, his eyes deeply sunken, but is a lecturer as strong as he ever could have been. His language is very simple too.

Darwin passed away in the year 1882, at the age of seventy-three. Out of the simple and quiet life at Down he had sent forth the great upheaval and revolution.

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....