THE STANDPOINT OF BIOLOGISTS.
_Lamarck’s View on Heredity._
In this chapter I shall invite attention to what the biologists
have discovered concerning racial change, and the conditions under
which the change occurs.
Before the simultaneous publication in 1858 by Darwin and Wallace
of their “Law of Natural Selection,” biologists believed in the
Lamarckian view of heredity, a notable follower of Lamarck being
our own Herbert Spencer. Lamarck briefly sums up his views in the
following passage: “All that nature has caused individuals to acquire
or lose through the circumstances to which their race has found
itself for a time exposed, and consequently, through the predominant
exercise of certain organs, or through a failure to exercise certain
parts, it preserves through heredity to the new individuals that are
produced by them, provided the changes acquired are common to the
two sexes, or to those that have produced these new individuals.”
Now this view is the one that is popularly held to this day, and
it is the very view which the new school of biologists have set
themselves to combat.
Lamarck would have accounted for the long neck of the giraffe by
supposing that in remote ages its ancestors were short-necked like
other animals, but that it exercised this neck in browsing off high
trees, that the necks elongated in consequence of this stretching,
and that this elongation was transmitted by heredity, although even
by imperceptibly slight degrees, from one generation to another,
until the part gradually grew to the present length. Lamarck would
cordially have agreed with the modern educationalist in the belief
that the children of a man who gives himself to learning will
have better head-pieces than if the father had been a soldier or
professional cricketer.
In this Lamarckian view of heredity we have two ideas; first, that
fresh characters may be acquired during an individual’s lifetime,
due to the action of his surroundings or environment; and secondly,
that these fresh characters are transmitted to the offspring and may
produce in time marked racial change. The first idea is undoubtedly
and admittedly true. The build of a soldier, a clerk, a ploughman,
and an athlete is distinctive; the horn that grows upon a mechanic’s
hand, and the development of the muscles of a blacksmith’s arm, are
commonplace facts. It is the second idea, the supposed transmission
of these acquired characters, which is now so seriously called in
question.
_Darwin’s Law of Selection._
The law of selection brought forward by Darwin and Wallace may be
stated as follows:--No two offspring of the same parents are quite
similar to each other, indeed they often vary to a considerable
extent. Under the conditions in which they live, some of these
offspring will have an advantage over the rest, dependent upon an
inborn peculiarity. Inasmuch, therefore, as more progeny are produced
than can ever survive, those most fitted to these surroundings will
have the better chance of living. These will, in larger numbers,
perpetuate the race and transmit their inborn qualities to the
race, thus gradually eliminating the less suitable ones.
Keeping to the case of the giraffe, Darwin and Wallace would
explain the length of the neck somewhat as follows: With Lamarck
they believe that the ancestor was short-necked, but the subsequent
elongation they would explain in quite another way. They would
take for granted that there are times when grass and foliage are
scarce, that short-necked animals would soon exhaust the herbage
and shrubs, but that the taller shrubs and trees would afford
subsistence to animals with a higher reach. Amongst the ancestral
giraffes those born with the longest necks would at such times have
an advantage over the rest, who in large numbers would die out.
The longer necked ones, more suited to their environment, would
perpetuate their inborn quality of long-neckedness: of the next
generation those again with the longest necks would survive, and
so on. The Darwin and Wallace school of thinkers would, I quite
believe, be prepared to state that by attention to education it
would be possible to improve the mental qualities of the race,
but they would teach that this improvement could only take place
provided that the system made it possible for the clever man and
woman to earn a better livelihood, _marry early_, and _have large
families_, while the stupid ones should produce fewer children, a
condition which at present is far from being the rule.
[Illustration: FIG. 1.
Diagram to illustrate: A, the transmission of acquired characters,
B, modification of type by natural selection. In A an individual of
rounded proportions, at the top of the diagram, has two children.
Environment is represented by a board with holes through which they
must pass. In so doing they become thinner, transmit the thinness
to their children, and so on. In B, a man of rounded proportions
has two sons who vary, one being fat, the other thin. The fat one
cannot get through the hole in the board; but the thin one does,
has children who again vary, the thin one having an advantage.]
_Three Ideas involved in Selection._
Now there are three ideas in this law of natural selection: first,
that there are inborn variations among the offspring even of the
same family; secondly, that these various individuals living in
surrounding conditions on the whole uniform and common to all of
them, will start in life, some with an advantage and others with
a relative disadvantage, and that those possessing an advantage
will, more of them, tend to produce offspring; thirdly, that the
variations, inborn in this case and not acquired, will probably be
transmitted. That there are marked variations--physical, mental, and
moral--among a litter of kittens or puppies is within the experience
of everyone who has kept them, and that variations in human families
are as marked is known to everyone who has brothers and sisters.
Even twins frequently differ considerably from each other, and it
is said that the last years of the lives of the Siamese twins were
sadly marred by their opposing views as to the rights and wrongs
of the American Civil War! It stands to reason also that these
variations may be of advantage or disadvantage to their possessors,
and that among animals and plants, where there are no social props
given to the weak, the variations may and do determine survival.
To give an idea of the rigorous operation of selection which we
find among the lower animals, we have only to enumerate the number
of the progeny produced by each pair, which is often prodigious,
and knowing as we do that the number of individuals in a species
remain virtually the same in a given district for long periods of
time together, we conclude that the room of the parents is just
filled by a younger pair, and all the excess of their progeny over
and above this one pair must have succumbed to surrounding want
and hardship. To give one concrete example out of hundreds that
might be selected, let us take the case of the golden eagle given
by Weismann in his essay on the “Duration of Life.” He says: “Let
us fix the duration of life in the golden eagle at sixty years, and
its period of immaturity (of which the length is not exactly known)
at ten years, and let us assume that it lays two eggs a year, then
a pair will produce one hundred eggs in fifty years, and of these
only two will develop into adult birds, and thus on an average a
pair of eagles will only succeed in bringing a pair of young to
maturity once in fifty years; and so far from being an exaggeration,
this calculation rather under-estimates the proportion of mortality
among the young.”
But in all probability most of us are more conversant with the ways
of the domesticated cat than with those of the golden eagle. The cat
produces its first litter of three or four before it is a year old.
Its kitten-producing life lasts, say, for eight years, and it may, on
a low estimate, be supposed to produce a litter of four kittens once
in each year. In all a cat will have, on a fair estimate, thirty-two
kittens, and may be a great-great-great-great-great-great-grandmother
in her lifetime, yet we do not observe in town or village such an
alarming increase in the cats from year to year. Their number is
pretty stationary, kept so by the enormous destruction of their
progeny. The enormous capacity for reproduction of a race of
animals, where for a time their surroundings are favourable, will
be appreciated by the lowland farmers whose fields were laid waste
a few years ago by armies of short-tailed field-mice, whose natural
enemies, the hawks, the cats, and the weasels, had been extensively
shot or trapped.
The struggle to survive among the savage tribes of man must be
excessive. Whole races come and go, and their survivors again fall
victims to privations, disease, or natural enemies, before the
white man with his better brain and capacity for adaptation.
_Selection is a Fact, not a Theory._
The third idea in the law of natural selection--namely, that inborn
variations are transmitted--is also a fact that is universally
admitted not only among biologists at the present day, but by those
who trust only to their everyday experience. “The child has its
father’s temper,” or “its mother’s eyes,” are expressions heard in
every nursery, while the innumerable cases of the transmission of
inborn drooping eyelids and supernumerary fingers and toes show
the same thing in a more striking manner.
The law of selection is therefore no mere unproved fancy, it is a
statement of fact, and of one which is so obviously true that it is
now almost universally admitted, not only among specialists, but
by most intelligent and educated persons. It was understood, and
its significance partly appreciated by Malthus, and I find that
even he acknowledges a prior claim of Franklin’s.[2] Romanes[3]
tells us that the idea occurred in 1813 to Dr. Wells, and in 1831
to Mr. Patrick Matthew, and the wonder is that other thinkers have
passed unnoticed such an obvious phenomenon.
_How much is explainable by Selection?_
While, however, natural selection as an agent capable of producing
racial change is accepted by almost every well-instructed biologist,
there are some who are still inclined to give some value to the
operation of the Lamarckian transmission of acquired characters.
They do not deny that to selection is due by far the most obvious
racial changes, and that experimentally the most potent factor in
the production of a new variety of a plant or animal is selection.
They are, however, inclined to believe that along with this, there
may be some transmission of acquired character, only discernible
after the lapse of many generations. Darwin himself thought that this
was the case; he held that certain racial distinctions were due to
the action of the environment on the parents and the transmission
of the change thus produced upon their offspring. In his great work
upon “The Variation of Animals and Plants under Domestication,”[4]
he enumerates some of these. They may be divided roughly into two
classes: first, instincts and habits; and, secondly, results of
use and disuse. Darwin believed that the trained habits of dogs
and horses, the tameness of the rabbit and other domestic animals,
were due to the direct and transmitted effects of man’s contact. He
held that the large size of the leg and small size of the wing of
the domestic as compared with the wild duck are gradually acquired
and transmitted by use and disuse.
But Darwin, as Huxley points out,[5] was inclined to lay less
stress upon the transmission of acquired characters in his later
writings; and we find that in the “Origin of Species” he is inclined
to abandon them altogether, and accept the position now held by the
Neo-Darwinian School of Galton and Weismann. He says (pp. 117, 118),
“If under changed conditions of life, a structure, before useful,
becomes less useful, its diminution will be favoured, for it will
profit the individual not to have its nourishment wasted in building
up useless structures.... Thus, I believe, natural selection will
tend in the long run to reduce any part of the organism as soon as
it becomes through changed habits superfluous.”
Just as Darwin himself, as time went on, laid more and more stress
upon the importance of selection, and less and less upon the
transmission of acquired characters, most naturalists have tended
to follow him in the same direction. It may be said, I think,
without gainsay, that, since Darwin’s death, the most important
and outstanding work done by the biologists has been the uprooting
of much of the Lamarckian doctrine, originally held, not without
question, however, by Darwin himself. The biologist of to-day is
more Darwinian than Darwin, and explains on the Darwinian hypothesis
even those cases which had presented difficulties to Darwin’s own
mind.
_Galton and Weismann._
Amongst those who were pioneers are Galton and Weismann, and,
curiously enough, in England and Germany these two men, independently
of each other, came to the same conclusion respecting the
non-inheritance of acquired qualities, and pointed out that the
facts of development indicate that the generative matter is passed
on from one generation to another, remaining intact in the body of
the parent, and that we have no reason to suppose that it could be
influenced by changes in other parts of the parental organism. It is
not uninteresting to note and contrast in these two investigators
the action of the typically English and typically German mind, more
especially as the comparison is perhaps equally complimentary to
the two nationalities, and indicates the value of results arrived
at by workers of different individualities.
Galton was first in the field, and as long ago as 1876[6] made the
following clear and concise statement:--“The conclusion to be drawn
from the foregoing arguments is that we might almost reserve our
belief that the structural cells can react on the sexual elements
at all, and we may be confident that at most they do so in a very
faint degree: in other words, that acquired modifications are
barely, if at all, inherited in the correct sense of the term.”
Thirteen years later[7] he expresses himself in practically the
same terms. An untiring investigator, chiefly in the facts of human
heredity, he briefly sums up as above one of his most important
general conclusions. It is all he has to say, it is all that his
facts permit him to say.
In 1882, Weismann[8] questioned whether there is as yet any proof that
acquired characters are transmitted; he writes:--“The theoretical
conception of variation as a reaction of the organism to external
influences has also not yet been experimentally shown to be correct.
Our experiments are still too coarse, as compared with the fine
distinctions which separate one individual from another, and the
difficulty of obtaining clear results is greatly increased by the
circumstance that a portion of the individual difference always
depends upon heredity, so that it is frequently not only difficult,
but absolutely impossible, to separate those which are inherited
from those which are acquired.”
Since that time, Weismann, in a series of important essays,[9]
indicating a profound knowledge not only of comparative morphology,
but of the habits and modes of life of a vast number of animals and
plants, has shown that many of the cases which Darwin was doubtful
about may reasonably be explained by selection, and he has marshalled
a vast mass of evidence in support of the argument that acquired
characters, experimentally produced, are not transmitted.
These essays are profoundly interesting, and will supply food for
thought for many years, but it must be admitted that Weismann has
gradually been led away to speculations of the most elaborate kind,
built upon the most flimsy substratum of fact. There is evidence
of this tendency even in his early writings, but in his later
essays, especially his recent work on “The Germ Plasm: a Theory of
Heredity,”[10] the speculative part quite overpowers the rest.
As those who are interested in heredity will probably read his works
with the greatest attention, I have ventured in an appendix to
make clear what in his works may, in my opinion, safely be looked
upon as speculative rather than legitimate, or even provisional,
generalisation, and what, therefore, may be altogether omitted from
the study of a practical problem such as that with which we are
concerned.
_Are Acquired Characters transmitted?_
The practical issues which both Galton and Weismann have raised
cannot, however, be underestimated, and, in respect to the
non-inheritance of acquired characters, the mass of modern thinkers
may already be said to have given their allegiance to the views of
those two thinkers.
But we are living in times when mere authority is at a discount,
and we may well demand the facts for ourselves. The point which
we are inclined to question is one as to which a doubt was often
present in Darwin’s mind. Granted that selection is a factor, we are
inclined to believe that the transmission of acquired characters
must also take place, at any rate, to some extent. In attempting
to decide this question upon the facts themselves we may take two
lines of research. In the first place, we may examine every case
of racial change, the production of new or different parts, the
development of a new instinct, or the degeneration or loss of parts
or instincts present at some past epoch. If in every case we are
not compelled to exclude natural selection, and if in every case
that we can directly and experimentally follow, selection is the
outstanding factor, then there is strong presumptive evidence that
racial change is caused by selection and not by the inheritance
of acquired characters. In the second place, we may artificially
induce the acquisition of some character, and notice whether this
is transmitted; if it is not, then the general operation of this
kind of transmission is rendered very doubtful.
_Many Cases of Supposed Transmission to be explained by Selection._
It is upon these two lines that Galton and Weismann worked, and
we may now follow in rough outline the evidence they adduced.
Darwin had been able to explain, to universal satisfaction, the
evolution of many types and varieties, as a result of selection
alone; though certain cases of the supposed inheritance of use
and disuse, and of acquired instincts, caused at times doubts to
arise in his mind. But Weismann has questioned this inheritance,
and has shown that--as Darwin himself sometimes believed--these
may readily be explained by selection alone. The gradual increase,
generation after generation, in the size of a useful limb or the
perfection of a valuable organ of sense may readily be explained by
selection. The fact that the limb or organ is of use to the race in
its struggle will determine the survival of those born with these
serviceable parts well-formed, and these in their turn will produce
others as favourably or more favourably constituted, from whom
further selection can take place. We cannot shut our eyes to the
operation of selection in such instances, nor have we any reason
for saying that part of the effect must be due to some other cause.
In the case of organs which become useless and finally disappear
in the course of generations, a selective agency will sufficiently
account for this disappearance. As Darwin himself pointed out, a
useless organ is an expense and a drain upon an animal’s capital;
it requires blood, and its exercise uses up some of the sum total
of energy the animal possesses. The truth of this can be shown
experimentally, as when compensatory growth occurs in the rest of
the body after amputation of a limb, or when one lung or kidney
enlarges subsequently to the disease or removal of the other. In
cases where an organ is useless, those who have it badly developed,
and in consequence have other and useful parts more fully formed,
will have a distinct advantage over those born with a well-formed
but useless organ. We may thus explain the small size of the wings
of the tame as compared with the wild duck, an instance in which
Darwin saw difficulty in excluding inherited disuse. In this way we
may explain the occurrence of the still smaller wings of the running
ostrich and apteryx; also the blind fish of the Kentucky Cave, and
the visionless eyes of the burrowing mole. As an illustration, an
animal or man may, in this respect, be compared to an individual
with a given amount of capital, who, if he spends his money in
one direction, will thereby have less for another purpose. In this
way a big leg may be obtained at the expense of a small arm, or a
good ear be the cause of an indifferent eye.
When we turn to the question of the supposed transmission of acquired
instincts and habits, we find that it is possible by means of the
principle of selection, to explain some, at least, of the cases
which presented difficulties to Darwin’s mind. Thus the tameness of
rabbits, cats, and dogs, which animals have for countless generations
been subjected to domestication, need not necessarily be accounted
for by supposing that the results of training are transmitted.
For it is easy to understand how those that would have rebelled
most against man’s authority, and who were by nature the least
tractable, would have been less cared for by man, and probably would
finally have suffered extermination, while the docile received his
attention, and were allowed to reach maturity and perpetuate the
race. That this selection must be going on at the present time is
very obvious, and as instances we may note the savage dogs that are
constantly being destroyed, and the house dogs and domestic pets
that are, in most cases, continually being selected from the docile
animals and those of good temper. A dog that does not possess these
good qualities can have no existence in town or village, and so by
continual extermination of the unfriendly, the “friend of man”
has gradually been evolved.
_Paucity of Experimental Evidence of such Transmission._
Turning now to those cases in which characters can be acquired or
experimentally stamped upon an individual, we find that no single
reliable instance can be adduced in which transmission takes place.
Mutilations have been practised upon male infants by Jews and other
Semitic races for thousands of years; yet, in spite of this, the
operation has still to be performed, for the lost parts appear in
the offspring of to-day as in the earlier periods of their race’s
history. Certain breeds of dogs and sheep have for many generations
been systematically docked, and yet the young are born with as
long tails as those of other breeds. Chinese women have compressed
their feet from times long past in their history, yet Chinese
female infants are still born with large feet, and have to undergo
afresh the torture of their compression. More curious still, for
it affects an organ of paramount importance, the brain, there is a
tribe of Indians who flatten their heads in early life, entirely
changing the shape not only of the skull, but of the brain itself,
yet their children are born with normal rounded heads; the induced
change is not transmitted.
It must be admitted that this evidence is pretty strong, and we
need not wonder that it has produced such widespread conviction,
although it has been so lately taken up by the thinking public.
_The Reproductive and the Body Cells._
The body of a plant or animal is composed of small living bodies,
most of them of microscopic size, called cells. These lead, to a
certain extent, individual lives, and have individual characters,
but they are built, as it were, together, like the bricks and stones
of a house, to form the body. The cells are, all of them, nourished
by the blood and lymph, and some are connected together by strands
of connecting matter termed nerves. All the cells of the body are
descendants from a single fertilised egg, which has resulted from
the fusion of a paternal and maternal sexual cell. Among the cells
of the body, and situated in special organs, are the sexual cells,
likewise nourished by blood, but not connected by nerves with other
parts of the body.
_Reproductive Cells unaffected by Local Changes in the Body Cells._
Now there is no reason to suppose that these sexual cells residing
in the bodies of the parent will be influenced by a change in the
muscle or brain cells of the parent unless this change in some
way or another influences the blood, the common go-between. But
the blood is now known to be but a food and oxygen carrier, and
an eliminator of used-up products. It is like a river laden with
vessels carrying corn for the food of the big city, and nothing
more. The life, the energy, the character of the body is the sum of
the lives, the energies, and the characters of the cells--although
these necessarily require the nourishment derived from healthy
blood--just as the life of the city is the sum of the life of its
citizens who require the nourishment of the corn.
_Constitutional Change may, though it rarely does, affect the
Reproductive Cell._
Let us suppose that an average healthy man during his lifetime
acquires, by use, accident, or disease, some change in his right
arm. There is no reason to suppose that the sexual cells, rather
than any other cells in the body, will be affected. If, on the other
hand, this local change in the arm affects the blood, depriving it
of nutritive power, or casting into it obnoxious matter, then it is
possible that all the cells of the body may be affected. We have many
instances of such a thing, as when the blood and whole constitution
are involved after maybe a primary local affection, and when, in
consequence, the hair drops off, or marks and irregularities of the
nails appear. In these cases the sexual cells may suffer from want
of nourishment, or from what we may term a poison, and may produce
less vigorous and perhaps diseased or malformed offspring, but they
will show no tendency to develop in the offspring that primary local
affection which caused ailment in the parent. But, as we shall
see in the next chapter, the sexual cells in most cases get off
scot-free, and the most dangerous acquired constitutional diseases
leave no trace of their passage upon the reproductive elements. It
is indeed difficult to point to a case, with the notable exception
of syphilis, in which acquired constitutional blood disorders leave
any trace in the organisation of the progeny, and we are indeed
fortunate that this is so.
There seems to be some evidence that we may stunt the growth of a
plant or animal by insufficient or unsuitable food, and that all the
cells of the body may thereby be reduced in size, the sexual cells
among the rest, and that these reduced cells give rise to small
progeny in the next generation. Here again the evidence in the case
of animals seems rather doubtful, and rests on a few statements,
such as that of De Quatrefages, that horses taken from Normandy to
the hilly and less fertile country in Brittany become distinctly
smaller in the course of three generations. In our own country
large horses are found in the plains and small horses and ponies in
the hilly districts of Wales and Scotland. But the obvious utility
to man of small breeds in hilly districts, and of heavily-built
horses on the plains, and the fact that horses have been bred for
hundreds of years in view of their services to man, throws great
doubt upon this particular evidence of De Quatrefages’, and we may
well leave it out of account, unaccompanied as it is with evidence
as to the total exclusion of the interbreeding of the Normandy with
the Brittany variety.
On the other hand, among plants it really appears as if by adjusting
the soil and climate you may produce stunted varieties, whose seed
produce small plants. The poor and exposed ground of our hilltops
are covered with dwarfed varieties of the bigger plants growing
luxuriously in the adjacent plains, and a classical case mentioned
by Lemaire[11] is that of the hemp which, removed from Piedmont
to the less suitable soil of France, becomes a smaller variety,
growing to only half its former height in the course of two or three
generations. The enormous dwarfing that one can subject a plant to
is illustrated in the case of the conifer, which the Japanese can
cause to remain the size of a tiny shrub during its hundred years’
growth, by simply keeping the soil at the starvation edge, and by
pruning the branches and roots.
It appears then to be pretty certain that every man and woman
possesses a store of sexual cells, derived directly from the original
sexual cells from which he or she was developed. These in the main
are like the original cell, being as they are of its substance, but
they show minor differences amongst themselves, and give rise in their
turn to offspring no two of which are alike. These sexual cells,
residing within the paternal or maternal body, are uninfluenced by
the course of life led by that body, except, perhaps, in some few
cases in which the whole system and the blood are impoverished,
saturated with alcohol, or infected with the microbes of disease,
which microbes in some cases, perhaps, directly attack the sexual
cells.
_The Facts of Evolutive Selection known to the Gardener and Breeder._
Scientific men are often very slow at arriving at a truth, and
there are many instances of valuable knowledge held by sections
of the people in perhaps an empirical fashion, which has at last
found acceptance by the learned. The practical results of all
this biological teaching has been in the hands of cattle-breeders
and nurserymen for centuries. The various breeds of cattle have
been produced by man, not by any new method of ventilating the
cow-sheds, or by some freshly discovered patent fodder, but simply
by selecting for breeding purposes those individuals that most
suited the breeder’s purpose. The racing stallion was kept which
most resembled a greyhound, the hog that most resembled a beer
barrel, and the cow that gave the best combination of milk and
flesh. The gardener produces the hundreds of new varieties placed
every year in the market by keeping the seeds and propagating from
any variety he may wish to perpetuate, and these varieties are
always spontaneously occurring. He perfects his stock by selecting
the seed only from the very best.
The testimony not only of the learned but of those who in their
lives, unbiassed by any theory, have been engaged in modifying breeds
of animals and plants, is unanimously in favour of the view that
selection is the only, or, at any rate, by far the most powerful
factor in producing racial change. So far these facts have had little
or no application to the question of human race progress. People
are still too much biassed by archaic anthropocentric ideas; they
view man by himself, under his own special laws, and would often be
shocked by an attempt to draw obvious parallels between him and the
lower animals. Amongst the thinking few this attitude has changed,
and broader and sounder views are rapidly gaining ground.
People, too, are apt to feel what may be called a false delicacy
in speaking of questions relating to race change, but this may more
rightly be termed the shyness necessarily associated with an unusual
topic of discussion. We English laugh at the American woman who, from
notions of extreme modesty, will not speak of the “leg” of a piano;
but we in our turn draw our own often exaggerated lines, beyond
which we will not pass. Just as there is no subject which will not
yield food for the evil-minded, so there is no subject--having to
do with the laws of nature--which cannot be naturally approached
in all simple-mindedness. As soon, therefore, as it is realised,
that this question we are dealing with is one which demands not
only our closest attention, but also the advantage of public and
private discussion, so soon shall we have acquired the habit of
regarding it in quite a matter-of-fact and pure-minded way.
FOOTNOTES
[2] “Franklin’s Miscellany,” p. 9.
[3] “Darwin and after Darwin,” vol. i., p. 257.
[4] Chapter xxvii., vol. ii., 1875.
[5] “Life and Letters,” vol. ii., p. 14.
[6] “Journal of the Anthropological Institute,” vol. v., pp. 344–7.
[7] “Natural Inheritance” (1889), p. 14.
[8] “Studies in the Theory of Descent,” translated by Raphael
Meldola, p. 692.
[9] “Essays upon Heredity,” translated by Poulton, Schönland and
Shipley; vol. i. published in 1889, vol. ii. in 1892.
[10] Translated by W. Newton Parker (1893).
[11] D’Orbigny’s “Dictionary.”