pure and simple, who maintain that Lamarck’s theory in itself explains
all the phenomena, and that Darwin’s principle of selection is not
only invalid but superfluous. This school is practically extinct,
though Packard often sails to its very edge in his efforts to
defend his subject, as is the manner of biographers. (2) The Neo-
(New)- Lamarckians who develop Lamarck’s theory and add to it Darwin’s
selective principle as of greater, equal, or secondary importance,
according as they lean the more strongly to Darwin or Lamarck. This
position held the field almost alone, until Weismann fired his opening
gun in 1883. He founded (3) the Neo-Darwinian school which repudiates
altogether the Lamarckian factor of the hereditary transmission of
acquired characters, and maintains that Darwin’s theory is able to
dispense with Lamarckian ideas of use and disuse.
As Weismann is the storm center of the controversy we will now examine
his theory.
In 1883 Weismann became the pro-Rector of the University of Freiburg
and in the hall of the University, in June of that year, he publicly
delivered his inaugural lecture “On Heredity.” This lecture is
generally regarded as the first broadside in that war which filled
with its reverberations the scientific magazines of the world for the
next thirteen years. As one writer aptly says, “The warring scientists
splashed like irate cuttle-fishes in clouds of their own ink.” About
1896 however, the public grew tired of the never-ending flood of
biological lore on what looked to the lay mind like an insoluble
problem. The editors, with their fingers on the public pulse, cried,
“A plague on both your houses,” and sent the savants to seek in their
laboratories the victories denied to their pens.
As a matter of fact however, the coming struggle was foreshadowed in a
paper read by Weismann at the meeting of the Association of the German
Naturalists at Salzburg, two years earlier, in 1881.
This paper was entitled “The Duration of Life,” and the subject was
still further developed in an academic lecture, in 1883, on “Life and
Death.” These two biological contributions not only indicated the
foundations of Weismann’s theory, but they threw a very brilliant light
in certain very dark places. Weismann not only took up, but he solved
the hitherto obscure question of the origin of death.
Johannes Muller had, as early as 1840, rejected the prevailing
hypothesis which held the death of animals to be due to “the influences
of the organic environment, which gradually wear away the life of
the individual.” Muller argued that if this were so “the organic
energy of an individual would steadily decrease from the beginning.”
Everybody knows, however, that in spite of the wear and tear caused
by the “environment,” be it organic or inorganic, the volume of life
increases, until a certain stage is reached in all animals. But Muller
had failed to fill the gap his criticism had created.
This problem Weismann solved by analysing the methods of reproduction
among animals. These generally speaking are two; sexual, and non-sexual
or, as it is sometimes termed, a-sexual. This latter form is the mode
that prevails at the bottom of the organic scale--among the protozoa,
animals consisting of a single cell. This method has a variety of forms
which are classified by Haeckel as (1) self-division; (2) formation of
buds; (3) the formation of germ-cells or spores. We shall here deal
only with the first, self-division, or fission, which is the most
universal of all methods of propagation, being the progress by which
the individual cells which compose all the higher animals multiply
themselves. This is the method vital to Weismann’s theory and the other
two are no more than distinct modifications of fission.
When a Moneron or an Amoeba reaches a certain size, it begins to pinch
in the middle like a tightly-laced corset. This increases until the
creature divides into two equal halves. Each of these halves becomes a
complete individual which continues to thrive until the next division
takes place.
What Weismann observed as the most significant thing about this was
that in this process and among these unicellular (single celled)
organisms there is no such thing as natural death. Accidental death
is wholesale in its proportions, but no Moneron ever dies of old age.
Astounding as it may seem to the layman, the race-old, world-wide idea
that death is “essential to the very nature of life itself” is here
totally and indisputably overthrown.
“I pointed out,” says Weismann, in the second lecture and referring to
the first “that we could not speak of natural death among unicellular
animals, for their growth has no termination which is comparable with
death. The origin of new individuals is not connected with the death of
the old; but increase by division takes place in such a way that the
two parts into which an organism separates are exactly equivalent to
one another, and neither of them is older or younger than the other.
In this way countless numbers of individuals arise, each of which is
as old as the species itself, while each possesses the capability of
living on indefinitely, by means of divisions.”
Among the Metazoa, i. e., multicellular or many celled animals, this
immortality of the individual disappears. “Here, also,” says Weismann,
“reproduction takes place by means of cell-division, but every cell
does not possess the power of reproducing the whole organism. The
cells of the organism are differentiated into two essentially different
groups, the reproductive cells--ova or spermatozoa--and the somatic
cells, or cells of the body. The immortality of the unicellular
organism has passed over to the former--the reproductive cells--the
others must die, and since the body of the individual is chiefly
composed of them, it must die also.”
And so death came into the world, not by sin, as the Genesis legend
reports, but through sex; a most astonishing conclusion, it may be,
but one from which there is apparently no escape. Immortality still
remains, it is true, but it is not the immortality of the conscious
self. Positive science, nothwithstanding all its glorious gifts,
has dealt a terrible blow to those gorgeous dreams of primitive men
and modern mystics; those hopes and longings which have sustained
millions of our race in hours of supreme sorrow; a blow which not
even the bravest has been able to receive without flinching. The
only immortality of which science has any surety is that of these
unconscious single cells, which make possible the reproduction of the
species.
Weismann, then, divides the cells which compose the bodies of the
higher animals, including man, into two distinct kinds; the somatic,
or body cells and the germ, or reproductive cells. These germ cells
are, so to speak, batteries in which are stored a substance which
Weismann calls germ-plasm. A minutely small portion of this germ-plasm
from an individual of one sex, mixed with a similar portion from an
individual of the other will produce a new individual. But--and here
comes the keystone of Weismann’s arch--only a portion of the mixed
germ-plasm is used up in the composition of the new individual; the
rest is stored away in the germ-cells of the new individual for further
reproduction when the time arrives. The only relation that this
reserved germ-plasm has with the body cells of the new individual is
that it is provided by them with room and board.
Thus, according to Weismann, from generation to generation, there is
an unbroken stream of germ-plasm, and this constitutes his celebrated
theory of “The Continuity of Germ-Plasm.” Granted this theory as a
premise, and Weismann’s conclusions cannot be gainsaid. This germ-plasm
being the sole “carrier of heredity,” nothing that happens to the
somatic or body cells can be transmitted to the progeny.
Darwin had put forward a theory of heredity which he called
“Pangenesis,” which made out a good case for the admission of the
Lamarckian factor. According to this theory all the somatic or body
cells give forth still smaller cells which he calls “gemmules.”
These gemmules are collected, by some process not explained, in the
reproductive organs. Here they are in packets, and these “packets of
gemmules” are “the carriers of heredity.” One can easily see how by
this process the effects of use and disuse would be transmissible
for an organ shrunk by disuse would not be capably represented by an
efficient delegation of gemmules at the reproductive headquarters.
Speaking of this theory, Grant Allen in his biography of Darwin says,
“Let not the love of the biographer deceive us. Not to mince matters,
it was his one conspicuous failure, and is now pretty universally
admitted as such.” It must be remembered however, that Darwin was fully
aware of its purely speculative character and with his usual caution
entitled it the “Provisional Hypothesis of Pangenesis.”
Romanes, one of Weismann’s ablest critics, compares Weismann’s theory
with Darwin’s, and while he refuses to defend Pangenesis against
Weismann’s charge that it is a wholly unsupported speculation, he
replies by contending that the germ-plasm theory lives in precisely the
same kind of a glass house.
However that may be, it is quite clear that the germ-plasm theory
completely shuts out the Lamarckian factor of evolution in all cases
where propagation is sexual.
“But,” say the Neo-Lamarckians, “Darwinism in itself, merely assumes
variations without attempting to explain their origin. Natural
selection only explains the survival of the fittest; it tells us
nothing of what Prof. Cope calls the ‘Origin of the Fittest.’ There
must be variation before selection, whence then, comes this variation?”
To this question Weismann has a ready reply. “Variation is due to the
blending of two wholly different kinds of germ-plasm at conception,
producing at birth a result that is not, and cannot be, wholly like the
contributor of either.”
And now, at last, the great German is in a corner. If all variations
are due to congenital characters only, and these, of course, are only
possible because of the combinations secured by sexual reproduction,
how do variations arise among non-sexual organisms where such
combinations cannot exist?
This is indeed, a poser. But any rejoicing by Weismann’s opponents is
quite premature. The sagacity which set those opponents by the ears is
still available. There is no attempt to untie that knot; Weismann cuts
it with a knife. He empties his antagonist’s sails by a smiling and
gracious surrender. Below the sexually reproducing animals, he concedes
the operation of the Lamarckian factor. In that unicellular world it
is not a special cell that is passed on but the individual itself is
continued, and of course any character acquired by the individual will
be preserved along with the individual.
Thus then the region of controversy is limited to sexually reproducing
organisms and we come to the field where the fiercest fight was
made. Do these organisms transmit by heredity those characters or
peculiarities acquired by the individual during its own life-time? To
this question the Neo-Lamarckians gave a positive affirmative, which
Weismann met with an unwavering denial.
Weismann challenged his opponents to produce a single demonstration of
such a transmission. Here let us be clear as to what is meant by an
acquired character. For illustration, let us suppose a father leaves
his son an estate of a thousand acres. That is inheritance. If the son
leaves his son the same one thousand acres, that is still inheritance.
But if that son increases the estate, during his life-time to two
thousand, the second thousand is an “acquired character” of a property
nature. There the analogy ceases for there is no dispute as to his
ability to transmit both thousands to his heirs by inheritance.
But with “acquired characters” of a biological nature, Weismann
maintains this to be impossible. Many specific instances were put
forward in refutation of this contention. Herbert Spencer cited the
case of the supposed degeneration of the little toe in civilized man as
a result of the shoe wearing habit. This it was urged could only have
occurred through the transmission of acquired characters and not by
natural selection as this diminished toe could not be of any value in
the struggle for existence.
But it was shown by measuring the feet of savages, who do not wear
shoes, and whose ancestors never wore them, that the small toes of
savages had degenerated quite as much.
Then Cesare Lombroso entered the arena leading a camel. According to
the Italian criminologist, the camel’s hump had been first acquired by
bearing loads and then transmitted by heredity. From the fact that the
camel and the llama, which is smooth backed, have something in common,
he concludes that camels are really llamas that have recently acquired
a hump in the performance of their labors. Lombroso also supported his
hump theory by some statements about Hottentot women having developed
callouses on their hips by carrying their children on their backs.
Unfortunately all Lombroso’s ingenuity was wasted for we happen to
possess the geological record of the camel in good condition, and from
this history we know that the “ship of the desert” had his hump before
the human race appeared when according to Lombroso he should have been
a smooth-backed llama. Disappointed as Weismann’s critics were it was
hardly feasible to argue that the camel had gotten his hump in those
early times by placing loads on his own back.
It was clearly seen that if a case of the transmission of a mutilation
could be established, Weismann’s theory would be thereby demolished. A
remarkable attempt was made in this direction in 1887 at the meeting
of the Association of the German Naturalists at Wiesbaden. To that
dignified gathering came Dr. Zacharias with a number of tailless
cats. It was asserted that these cats had no tails because their
mother had lost her tail through having it run over by a cart wheel.
The examination of these specimens proved an entertaining diversion
from the regular proceedings, and Prof. Eimer took them seriously
enough to refer to them in a later work as “a valuable instance of the
transmission of mutilations.”
Weismann, however, refused to be put down. He insisted that in the
absence of absolute certainty as to the cart wheel incident, they
did not fulfill the first condition of scientific evidence, and Dr.
Zacharias wisely admitted later, that this point was well taken.
Prof. Poulton had described certain cats with extra toes which he had
kept under surveillance for seven generations. “It would be equally
justifiable,” says Weismann, “to derive cats with extra toes from an
ancestor whose toes had been trodden on, as to derive the tailless cats
of the Isle of Man from an ancestor of which the tail had been cut off
by a cart passing over it, and thus to regard the existence of the race
as a proof of the transmission of mutilations.”
Again Weismann points out that the absence of a tail may not be owing
to the mutilation of the mother but to the inherent taillessness of
an unknown father. He proceeds to relate how during the year that Dr.
Zacharias came with his collection, “My friend, Prof. Schottlius
brought me a kitten with an innate rudimentary tail, which he had
accidentally discovered as one of a family of kittens at Waldkirch,
a small town in the southern part of the Black Forest. A closer
investigation resulted in the following rather unexpected discovery.
For some time past, tailless kittens have frequently appeared in the
families of many different mother cats at Waldkirch, and this fact is
explained in the following manner. A clergyman, who lived for some time
at Waldkirch had married an English lady who possessed a tailless male
Manx cat. The probability that all the tailless cats in Waldkirch are
more or less distant descendants of that male cat amounts almost to
certainty. Since a male Manx cat has reached the Black Forest, it might
equally well arrive at some other place.”
This very same year a popular scientific journal came to the rescue of
the transmission theory with the following incident purporting to have
taken place 22 years before, in 1864. “A pregnant merino sheep broke
its right foreleg about two inches above the knee-joint; the limb was
put in splints and healed a long time before the following March, when
the animal produced young. The lamb possessed a ring of black wool from
two to three inches in breadth round the place at which the mother’s
leg had been broken, and upon the same leg.” When this incident was
related to Weismann, he replied, “It is a pity that the black wool
was not arranged in the form of the inscription ‘to the memory of the
fractured leg of my dear mother.’”
Writing in the following year Weismann says, “Furthermore, the
mutilations of certain parts of the human body, as practised by
different nations from time immemorial, have not in a single instance,
led to the malformation or reduction of the parts in question. Such
hereditary effects have been produced neither by circumcision nor the
removal of the front teeth, nor the boring of holes in the lips or
nose, nor the extraordinary artificial crushing and crippling of the
feet of Chinese women. No child among any of the nations referred to
possesses the slightest trace of these mutilations when born; they have
to be acquired anew in each generation.”
While it is undoubtedly true that much in Weismann’s position lacks
experimental demonstration, it is equally true that when the heat
of the discussion somewhat subsided, his theories were well to the
fore, and they have since secured a wide acceptance among competent
authorities. It is hardly to be expected that his two greatest
critics, Spencer and Haeckel, would look with much favor on a theory
the acceptance of which would make necessary the re-writing of those
many volumes which constitute their lifework. Lankester, himself no
mean authority, in translating Haeckel’s “History of Creation,” feels
constrained to say in the preface, “I feel it due to myself to state
that I do not agree with him as to a very large part of his views on
classification, and as to his belief in the necessity of assuming the
‘transmissibility of acquired characters.’ Readers who have gained an
interest in these questions from the brief statements of the present
work must, without assuming that Professor Haeckel’s judgment is final,
go on to study for themselves the works of Weismann and others which
are mentioned with perfect fairness in these pages.”
And Joseph McCabe, the translator of his “Riddle of the Universe,” and
“Last Words on Evolution,” has this to say in his introduction to the
latter, written two years ago, “To closer students, who are at times
impatient of the Lamarckian phraseology of Haeckel--to all, in fact,
who would like to see how the same evolutionary truths are expressed
without reliance on the inheritance of acquired characters,--I may
take the opportunity to say that I have translated for the same
publishers, Professor Guenther’s “Darwinism and the Problems of Life,”
which will shortly be in their hands.”
It must be admitted that the older view is much less favorable to the
Socialist position in sociology than the later theory of Weismann. It
is a matter of some satisfaction that so great a critic as Romanes
concedes the feasibility of Weismann’s theory while rejecting some of
the conclusions which he draws from it. “If Weismann’s theory is true,”
says Prof. David Starr-Jordan, “the whole literature of sociology will
have to be rewritten!” And another writer insisted that Weismann had
reopened the case for Socialism.
If it were true that the terrible results of the degrading conditions
forced upon the dwellers in the slums were transmitted to their
children by heredity, until in a few generations they became fixed
characters, the hopes of Socialists for a regenerated society would
be much more difficult to realize. In that case these unfortunate
creatures would continue to act in the same discouraging way for
several generations, no matter how their environment had been
transformed by the corporate action of society. This much at any rate,
Weismann has done for us, he has scientifically destroyed that lie.
In this respect, independent sociological experiments and
investigations have arrived at the same conclusions as Weismann. Prof.
John R. Commons by careful study, reached the following conclusions:
That 1.75 per cent of the population of the United States are
congenital defectives; that 3.25 per cent are induced defectives,
that is, they have not inherited their deficiency; that 2 per cent
are possessed of genius and will make their way under the hardest
conditions; that 2 per cent are below the Aryan brain level; and that
the remaining 91 per cent are normal persons who are neither good nor
bad, brilliant nor stupid, criminal nor virtuous, and whose future is
entirely decided by the environment which surrounds them during the
first fifteen years of their life.
Herman Whittaker, a magazine contributor, states that during eight
years in Canada 2,000 boys taken from the London slums by Dr. Barnado
passed under his observation on a farm colony. And although most of
them had served terms in jail, not more than one per cent reverted to
their own former habits, or the habits of their parents.
When it is charged that a transformed social environment will not
solve the problem presented by the slum, the sweatshop and the jail, as
Socialists assert, we are justified in nailing the statement as false,
and a libel on human nature. And in so doing, we are not sentimental
dreamers of dreams, crying for the moon, but rigid analysts and
investigators, and, as Lassalle once proudly said, “We have behind us
the science and the learning of our day.”
V.
DE VRIES’ “MUTATION.”
Orthodoxy received the most stunning blow ever given it, at the hands
of Charles Darwin, and it is ever on the lookout for an opportunity to
make reprisals. It is only necessary for some fledgling to challenge
Darwin’s theory of the origin of coral reefs and offer some grotesque
assumption in its place, and it is at once announced from a thousand
pulpits that Darwinism,--that enemy of God and man--is dead.
Hugo DeVries, however, could hardly be called a fledgling, and the
supporters of Darwin had real cause for apprehension, it would seem,
when the rumor gained ground that no less a person than the Amsterdam
professor had overthrown Darwin’s theory, and substituted one of his
own.
Alas, this latest “death of Darwinism” was no more fatal than its
numerous predecessors, as the following quotation from DeVries himself
will show:
“My work claims to be in full accord with the principles laid down
by Darwin.” And again, “To Darwin was reserved the task of bringing
the theory of common descent to its present high rank in scientific
and social philosophy.” And, “Notwithstanding all these apparently
unsurmountable difficulties, (absence of experimental evidence since
gathered) Darwin discovered the great principle which rules the
evolution of organisms. It is the principle of natural selection. It is
the sifting out of all organisms of minor worth through the struggle
for life.”
The greater part of the adverse criticism, aimed at Darwinism applies
only to the extravagant claims put forward by his overenthusiastic
disciples; claims not to be found in the works of Darwin himself. As we
shall see later, one of the greatest offenders in this respect was no
less a person than the co-discoverer of the selection theory--Alfred
Russell Wallace.
Of all the mischievous misconceptions of Darwin’s theory none have
worked so much harm as that which regards natural selection as the
active and efficient cause of evolution. Although evolution is an
established fact, our knowledge of its processes are incomplete and
must always remain so until we have solved that most vexed of all
biological problems, the “causes of variation.”