Ontogeny deals with the history of the germ from its beginning as
an egg to its full fruition as a fully developed individual or as
Haeckel defines it, “the history of the evolution of individual
human organisms.” Phylogeny is defined by the same authority as,
“the history of the evolution of the descent of man, that is, of the
evolution of the various animal forms through which, in the course of
countless ages, mankind has gradually passed to its present form.”
I mention these two sciences together because it is by comparing
them that their chief significance appears. It is one of the most
astonishing discoveries of science and at the same time one of the
most convincing proofs of evolution, that the whole process of the
development of the human race from the lowest or simplest forms, which
constitutes the subject-matter of phylogeny, is reproduced in brief in
the development of the embryo of the individual. This remarkable fact
Haeckel named “the biogenetic principle.”
Darwin’s chief claim however to a pedestal in the hall of fame rests on
his discovery of “natural selection.”
During his memorable voyage on “The Beagle” he observed that there was
no essential connection between a species’ reproductive powers and the
number of its population. As this discovery plays an important part
in his theory we will let him speak for himself. In his “Journal of
Researches” he gives the following case, with his conclusion: “I was
surprised to find, on counting the eggs of a large white Doris (a kind
of sea slug) how extraordinarily numerous they were. From two to five
eggs (each three thousandths of an inch in diameter) were contained in
a spherical little case. These were arranged two deep in transverse
rows forming a ribbon. The ribbon adhered to the rock in an oval
sphere. One which I found, measured nearly twenty inches in length and
half inch in breadth. By counting how many balls were contained in a
tenth of an inch in the row, and how many rows in an equal length of
the ribbon, on the most moderate computation there were six hundred
thousand eggs. Yet this Doris was certainly not very common: although I
was often searching under the stones I saw only seven individuals. No
fallacy is more common among naturalists, than that the numbers of an
individual species depend on its powers of propagation.”
This instance is moderate compared with multitudes of others. The
question then arises as to why, of such a numerous progeny, only a
sufficient number reach adult stage as will replace the parent stock so
that population remains practically stationary.
Here Darwin became indebted to Dr. Malthus who, but for that
indebtedness would have been forgotten ere this. In his “Essay on
Population” Malthus points out various “checks” to the increase of
population. His main theory was that the population tends to increase
more rapidly than the food supply. The Reverend Doctor, having begotten
twelve children of his own, felt “called” to point out to British
parents the desirability and even necessity of limiting their families
in the interest of society. Malthus applied his theory to human society
where it is palpably false. Darwin transferred it to the natural
world where it proved to be a great truth. The obvious explanation of
this paradox is: that man, by agriculture and industry, can increase
his food supply to a greater proportion than any probable or even
possible increase of population. Animals cannot; their food supply is
beyond their control; they have no power to artificially increase the
supply. This difference totally destroyed the value of Malthus’ book
as a treatise on political economy. His immortality is assured solely
because he accidentally contributed a link to Darwin’s chain.
And now Darwin has travelled on his great journey thus far: Animals
propagate enormously but their population generally does not increase.
The main reason for this, though there are others, is, that their
number is limited by the amount of food available. Therefore, if
two parents produce ten thousand only two or three individuals will
reach maturity: the rest will perish. The remainder of the problem,
which still remained for Darwin to solve, was: first, is there any law
which determines which shall survive and which shall be destroyed; and
second, if there is such a law, will that law explain and thus, at the
same time, prove, the origin of new species? It is precisely because
Darwin solved both points of this tremendous problem with a clear and
irrefutable affirmative that he occupies the foremost place in the
annals of science.
Professor John Fiske said: “There is one thing which a man of original
scientific or philosophical genius in a rightly ordered world should
never be called upon to do. He should never be called upon to earn a
living; for that is a wretched waste of energy, in which the highest
intellectual power is sure to suffer serious detriment, and runs the
risk of being frittered away into hopeless ruin.”
Whether Fiske was right or wrong the only pertinent point here is that
Darwin was spared that necessity.
To his great task he brought a patience that is almost without
parallel. One of his biographers, Grant Allen, tells us that: “His
uncle and father-in-law, Josiah Wedgwood, suggested to him that the
apparent sinking of stones on the surface might really be due to
earthworm castings. So, as soon as he had some land of his own to
experiment upon, he began in 1842, to spread broken chalk over a field
at Down, in which, twenty-nine years later in 1871, a trench was dug to
test the results. “What other naturalist,” asks Allen, ever waited so
long and so patiently to discover the upshot of a single experiment?
Is it wonderful that a man who worked like that should succeed, not by
faith but by logical power, in removing mountains?”
Darwin studied domestic animals. He observed how many, and how widely
different, races there are of horses, dogs, swine, poultry in general
and pigeons in particular. In each instance the many varieties are
derived from an original common stock, as domestic fowls from the
Indian jungle fowl, and pigeons from the old-world rock-dove.
“Derived,” but how--by what process? In the case of domestic creatures
this was not difficult to answer. It is accomplished by breeders
“selecting” the individuals to be bred from. In the case of pigeons,
which Darwin laid particular stress on the fancier seemed to be able
to obtain almost any kind of a bird by selecting as parents those
pigeons which had the desired characteristics developed to the most
pronounced degree, and then again selecting in the same way from their
progeny. In this way were produced birds so different from each other
and their ancestors as the tumbler, the fantail, the pouter, and about
a hundred and fifty other varieties. The same with horses. If the
breeder desired draught horses, he selected for parents those animals
with massive shoulders and sturdy limbs. When a racer wins a “classic”
race, it is at once sent to the stud-farm. Although in the zenith of
its powers it races no more; it is “selected” for another and more
important role--the reproduction and, it is hoped, the accentuation of
the characteristics which enabled it to outrun its competitors.
All this impressed on Darwin’s mind the importance of the word
“selection,” which appears in the title of his theory and the subtitle
of his epoch-making book. Could it be possible that nature contained
some principle or combination of principles, which performed among
wild animals a part analogous to that of the breeder, among domestic
animals? Darwin discovered that this is precisely what takes place.
His famous theory may be formulated under the three following heads:
(1) Heredity.
(2) Variation.
(3) The struggle for existence, with its resultant, survival of
the fittest.
Darwin requires very little of heredity, and what he does ask is beyond
dispute. It is enough for his theory if like begets like and “figs do
not grow on thistles.”
Similarly with variation, the demands of his hypothesis are very
slight. If it be conceded that variation is a fact, that offspring do
vary from their parents and each other, it is enough. And who will
dispute this in a world where no two creatures are exactly and in all
particulars alike? The apparent contradiction that, heredity demands
likeness, while variation requires difference, is confined to the
surface--it is not real. The likeness is general while the difference
is particular. A sheep may be born with shorter or longer legs, by
variation; but it will be a sheep and not a horse, by heredity.
As an example of the working of the theory let us take Lamarck’s piece
de resistance, the giraffe. Lamarck says: “We know that this animal,
the tallest of mammals, inhabits the interior of Africa, and that it
lives in localities where the earth, almost always arid and destitute
of herbage, obliges it to browse on the foliage of trees and to make
continual efforts to reach it. It has resulted from this habit,
maintained for a long period in all the individuals of its race, that
its forelegs have become longer than the hinder ones, and that its neck
is so elongated that the giraffe, without standing on its hind legs,
raises its head and reaches six meters in height (almost twenty feet).”
Lamarck thought this length of neck was acquired by “continual efforts
to reach,” or, as Alfred Russell Wallace puts it in his criticism of
Lamarck--“stretching.” Many critics ventilated their wit on this theory
of Lamarck’s, under the impression that they were lampooning Darwin’s
idea.
They made a blunder similar to that of those critics of Utopian
Socialism who labor under the pleasing delusion that they are riddling
the theories of Marx. Professor Ritchie has preserved a couple of
stanzas by a witty Scotch judge who aimed his poem at Darwin, but hit
Lamarck.
“A deer with a neck that was longer by half
Than the rest of his family, try not to laugh,
By stretching and stretching became a giraffe
Which nobody can deny.
That four-footed beast which we now call a whale,
Held his hind-legs so close that they grew to a tail,
Which he uses for threshing the sea, like a flail,
Which nobody can deny.”
But Darwin’s theory is altogether independent of the “stretching” idea.
The causes and origin of heredity and variation are up to this moment,
alike wrapped in mystery. But when science succeeds in penetrating
those secrets, it is extremely unlikely that Darwin’s theory will be
seriously weakened, no matter what the causes may prove to be.
Now about the giraffe. We will suppose, for the sake of illustration,
two giraffes, a male and a female, whose necks are precisely five feet
long. We will confine our illustration to the question of the neck
alone. We will suppose this particular pair to give birth to a family
of three. First comes heredity. All we ask of heredity is that the
young shall be giraffes, not camels or any other species; and this
heredity guarantees. Now comes variation. As this is an ideal case for
the purpose of illustrating the theory, we will have one of the three
shorter-necked than the parents, another the same length, while the
third has a longer neck--over five feet.
Now comes the struggle for existence. When this family of giraffes is
fairly grown and the new-comers are approaching breeding age--mark the
importance of this matter of “breeding age,” for the problem is to find
out how nature determines which shall be bred from--they are obliged
to forage for themselves. There is no pasture to graze; they live
in what is almost a desert. There are few shrubs; scarcely anything
but fairly high trees--from ten to twenty feet. If a giraffe breeder
had this matter in hand and he wished to increase the length of the
giraffe’s neck, the problem would be simple. He would select number
three with the longest neck, pair it with the longest necked member of
the opposite sex in some other family and the trick would be done. But
this is in Central Africa, where there is no breeder to interfere, and
the question is: can nature accomplish the same result without his help?
This is what happens. First the leaves are eaten from all the lower
branches as they are reached with the least effort. Then they go higher
and still higher until the point is reached where number one with the
shortest neck cannot reach any further and the terrible struggle for
existence begins. Number two sees no danger as yet and number three has
things all his own way. But with short-necked number one, a tragedy has
begun. Every day now sees the food further out of his reach and even
number two is obliged to reach out for his supply. The breeding time is
approaching but the longer necked and therefore well-fed and vigourous
females will have nothing to do with this wobbley starving creature,
and the longer necked, well-fed males shun the short-necked starving
females. If the starving ones mate, the mother dies before giving birth
to offspring, or she cannot get nourishment enough to rear her progeny;
in either case there is no effective succession. So the longer-necked
are the fittest and they survive. Thus does nature “select” one by the
negative process of destroying the rest, in about the same way as a man
“selects” one puppy in a litter by drowning the rest.
In the case of the puppies we may say “artificial selection;” in the
case of the giraffe it is “natural selection.” And this theory, simple
as it may seem here, revolutionized Biology.
It is worthy of note that “natural” selection has many advantages over
“artificial” selection. The breeder may be mistaken; he may select
the wrong puppy and drown its superior. The horse that won the great
race may have had a fleeter-footed companion in the same stable had
the trainer known how to develop his possibilities. The gardener may
have passed the best root or stem through carelessness. But nature
makes no such mistakes, or if she does she eventually redeems them. Her
method, while it is wholly fortuitous and unintelligent, is practically
infallible. The condition of survival is, adaptation to environment.
The very process of selection is, in itself, a sure test of fitness.
True, moral considerations are eliminated--at least in the non-social
world--yet nature offers something like a fair field and no favors.
When we speak of nature’s favorites, we simply mean those who are best
fitted to meet her hard conditions.
Take a row of celery plants, from which future seedlings are to be
“selected.”
In this instance, let us suppose, the quality desired is ability to
resist frost. How is the gardener to know which of fifty plants are the
“best” in this respect. He has no method of finding out with any degree
of certainty. But nature comes along some night with a sharp frost and
“selects” ten by killing forty. And the very act of this “natural”
selection proves that these ten are better able to withstand the frost
than their fellows.
Breeders of white sheep who supply the white wool market have a very
tangible guide--they kill every lamb that shows the least tinge of
black. But even here, nature is not to be out-done. In Virginia there
is--or at least was in Darwin’s day--a wild hog of pure black. One
of its staple foods was known as the “paint-root.” Any hog with the
least speck of white on its body was poisoned by this root while its
all-black brothers found it a health-sustaining and succulent food.
In an environment which remained constant and where a species of
animals had reached a population which strained the limits of
subsistence--food supply--those offspring which most closely resemble
their parents, who had won out in that environment, would again succeed
and be selected. While if the environment changed--became warmer or
colder for example--those descendants which happened to vary in a
direction making them better able to cope with the new conditions would
be selected for survival as against those who resembled their parents,
which parents had survived in their day because they were adapted to
the prior environment.
For example, a country is well supplied with water and it is as a
consequence fertile and “green.” In such a country green insects and
green reptiles will be selected, because a green background will render
them almost invisible to their enemies. Individuals of other colors
will make their appearance by variation, but they will be such plain
targets to their enemies, they will be devoured before they reach
breeding age and have a chance to reproduce the variation.
But suppose desiccation (drying up) sets in. The country loses
its water supply, as Krapotkin has shown to have been the case in
North-West Mongolia and East Turkestan, leading to the enforced exodus
of the barbarians. Now green will disappear and brown or yellow--say
brown--takes its place. While this change will not, so far as we know,
cause insects and lizards to breed brown instead of green, it will
ensure the survival or “selection” of such as are born brown and the
destruction of those who breed true to their green ancestors. Now every
atavistic return to green will be mercilessly weeded out, just as, when
the country was well-watered and green, every sporadic production of
brown was done to death.
This is the biological foundation of that environment philosophy which
now pervades all our thinking. Change the physical environment, says
the biologist, and the species will be transformed. Change the economic
environment, says the Socialist, and, if you make the right change, the
race will be redeemed. Both statements rest on the same fundamental
laws.
As the many and highly important implications of this theory, are fully
dealt with in subsequent lectures most of them will be passed here.
We may note however, that whenever any nation in the modern world,
produces, in the development of its industry, a Socialistic variation,
that new feature at once proves its utility and is “selected” in the
Darwinian sense, because it constitutes an advantage over the previous
form of social organization, in that particular. This is the reason
why the trust--which is socialistic and revolutionary in its essential
tendences--is always victorious, in spite of the foolish ravings of
the Hearst newspapers and the antediluvian twaddle of William Jennings
Bryan.
But Darwin’s crowning achievement is that he made the general theory of
evolution impregnable by thoroughly and conclusively demonstrating it
in his own field as a naturalist. From then on it was only a question
of time as to when its application would be universal.
Socialism may be defined as the application of the theory of evolution
to the phenomena of society. This is precisely what Marx and Engels
accomplished, and this why their work is so fundamentally opposed to
the conventional theories and theological superstitious current in
their time, and so fully in harmony with all the latest achievements in
the scientific world. History ceases to be a meaningless mass of war
and famine, bloodshed and cruelty. It becomes a panorama presenting the
development of society according to laws which may be understood and
with a future that may be measurably predicted.
It develops by the operation of forces that no man or class can wholly
stay or hinder. The power of those forces and the direction in which
they are now making has been well set forth by Victor Hugo by a very
striking simile in the following passage:
“We are in Russia. The Neva is frozen. Heavy carriages roll upon its
surface. They improvise a city. They lay out streets. They build
houses. They buy. They sell. They laugh. They dance. They permit
themselves anything. They even light fires on this water become
granite. There is winter, there is ice and they shall last forever. A
gleam pale and wan spreads over the sky and one would say that the sun
is dead. But no, thou art not dead, oh Liberty! At an hour when they
have most profoundly forgotten thee; at a moment when they least expect
thee, thou shall arise, oh, dazzling sight! Thou shalt shoot thy bright
and burning rays, thy heat, thy life, on all this mass of ice become
hideous and dead. Do you hear that dull thud, that crackling, deep and
dreadful? ’Tis the Neva tearing loose. You said it was granite. See it
splits like glass. ’Tis the breaking of the ice, I tell you. ’Tis the
water alive, joyous and terrible. Progress recommences. ’Tis humanity
again beginning its march. ’Tis the river which retakes its course,
uproots, mangles, strikes together, crushes and drowns in its waves
not only the empire of upstart Czar Nicholas, but all of the relics
of ancient and modern despotism. That trestle work floating away? It
is the throne. That other trestle? It is the scaffold. That old book,
half sunk? It is the old code of capitalist laws and morals. That old
rookery just sinking? It is a tenement house in which wage slaves
lived. See these all pass by; passing by never more to return; and for
this immense engulfing, for this supreme victory of life over death,
what has been the power necessary? One of thy looks, oh, sun! One
stroke of thy strong arm, oh, labor!”
IV.
WEISMANN’S THEORY OF HEREDITY.
The weak, untrained brain must have a conclusion. It cannot reserve
its decision or render an open verdict. It is completely at sea in the
scientific world where the most profound savant is often obliged to
say, “I don’t know.” In a crowded courtroom, ninety per cent of the
spectators have made up their minds that the prisoner is innocent or
guilty before the first witness is called or a line of the evidence
has been read. He has a square jaw, or bushy eyebrows, or thick lips,
or he shifts uneasily from one foot to the other, any or all which
proves to the simpletons back of the rail, that he must be guilty no
matter what the crime is, or what the evidence may be. If he has blue
eyes and fair hair and mustache, or a pleasant manner, or pretty hands
and the onlookers were to decide the matter, they would hardly convict
him on his own confession. In England, a judge is not placed on the
bench because he “stands in” with a ward boss, but because of his wide
scholarship and systematic training, and the reason advanced for this
method is, that only a scientific scholar can reserve his opinion until
all the evidence is in and then, if the case demands it, render an open
verdict.
With the vexed problem of heredity, which has been so much to the fore
in science for the last twenty-four years, while many great thinkers
have distinctly taken sides, it must be remembered that in many points
of great importance, the only possible verdict on the contentions of
either side, is one of “not proven.”
But although this controversy has split the evolutionists into two
camps, it in no way compromises the evolution theory itself. The
controversy is based on the admission of all the parties to it,
that evolution is granted, and the question at issue involves only
a difference as to how the acknowledged results are accomplished.
Evolution is no longer merely a theory, it is an established fact, and
is recognized as such by all who live in an intellectual atmosphere
belonging to this side of 1859, the year of the publication of the
“Origin of Species.”
Neither does the result of this discussion threaten, in any way, the
validity of the Darwinian theory of “Natural Selection.” All the
disputants are avowed Darwinians, and disagree only as to whether
Darwin’s theory is alone sufficient to account for the origin of new
species.
Professor Packard, Lamarck’s biographer, and one of his warmest
admirers, at the close of his chapter devoted to the denial of “pure”
Darwinism says: “We must never forget or under-estimate, however,
the inestimable value of the services rendered by Darwin, who by his
patience, industry, and rare genius for observation and experiment,
and his powers of lucid exposition, convinced the world of the truth
of evolution, with the result that it has transformed the philosophy
of our day. We are all evolutionists, though we may differ as to the
nature of the efficient causes.”