On December 8, 1879, when Darwin was in his seventieth year and I in my
twenty-second, I had the rare privilege of meeting him and looking
steadily in his face during a few moments’ conversation. It was in
Huxley’s laboratory, and I was at the time working upon the anatomy of
the Crustacea. The entry in my journal is as follows:
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.
V
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.