THE ORIGIN OF THE SEXES
“Before studying the sexual relations,
and their more or less regulated form in human
societies, it will not be out of place to say
a few words on reproduction in general, to sketch briefly
its physiology in so far as this is fundamental,
and, to show how tyrannical are the instincts
whose formation has been determined by physiological
causes.”-LETOURNEAU.
Let us now, as the first path of our
inquiry, turn our attention to that biological point
of view which is indispensable and fundamental if
we are to understand those primary emotions, impulses
and differences of the sexes, of deep organic origin,
which were rooted long ago in the lowest forms of
life, and hence were passed on to man from his pre-human
ancestors. No apology is needed for this inquiry;
for in these uncounted ancestral forces, dating back
to the remote beginnings of life, we shall find hints,
at least, of many things which lead up to and explain
those problems which must be solved, before we can
determine the true position of woman in the complex
sexual relations of our social life. We cannot
deny our lineage. The force which drove life
onwards from the start drives it still to-day.
The reproductive impulse is the chief motor of humanity;
our seed is eternal. And the point of view that
I wish to make clear is that the sex-impulses, which
are, as few will deny, the base of the present unrest
among women, have an inconceivably long history, and
thus spring up within us with a tremendous organic
momentum. To deny this force is futile, to suppress
it impossible; all that can be done is to so regulate
its expression that it may serve life instead of waste
it. Implanted in every normal life is an instinctive
desire to function in two ways: to grow and to
reproduce, from the simple cell to the highest type
of life, including man and woman, these two desires
are essential and imperative. The irresistible
Force of Life has been inherited by us from millions
of ancestral lovers. Only when furnished with
a re-interpretative clue to the origin of sex and its
functioning can we come to realise its strength and
its beauty, far stronger, far subtler, than we suspected
before. It is the shirking of these life-facts
that has resulted so often in error.
And let no one resent or think useless
such an analogy between animal love-matings and our
own. In tracing the evolution of our love-passions
from the sexual relations of other mammals, and back
to those of their ancestors, and to the humbler, though
scarcely less beautiful, ancestors of these, we shall
discover what must be considered as essential and
should be lasting, and what is false in the conditions
and character of the sexes to-day; and thereby we shall
gain at once warning in what directions to pause, and
new hope to send us forward. We shall learn that
there are factors in our sex-impulses that require
to be lived down as out-of-date and no longer beneficial
to the social needs of life. But encouragement
will come as, looking backwards, we learn how the
mighty dynamic of sex-love has evolved in fineness,
without losing its intensity, how it is tending to
become more mutual, more beautiful, more lasting.
And this gives us new hope to press forward on that
path which woman even now is travelling, wherein she
will be free from the risk of clinging to conditions
of the past, which for so long have dragged her evolution
in the mire.
The same force that pushed life into
existence tends to increase and perpetuate it.
For when the great Force of Life has once started,
the same movements which constitute that life continue,
and give rise to nutrition, the first of the great
faculties, or powers, of life. Then, after this
growth has been carried to a certain point, the organism
from the superabundance of nutrition is furnished with
a surplus growing energy, by means of which it reproduces
itself, whence arises the second of the great life
faculties. We thus have the two essential forces
of life-the preservative force and the reproductive
force, arising alike from nutrition. Food to
assure life and growth for the individual; reproduction,
an extension of the same process, to ensure the continuance
of the species. We thus see the truth of Haeckel’s
definition that “reproduction is a nutrition
and growth of the organism beyond its individual mass,”
or in biological formula, “a discontinuous growth."
It is well to grasp at once this first
conception of reproduction as simply an extension
of nutrition, if we are to free our minds from misconception.
It is a common belief that the original purpose of
sex is to ensure reproduction, whereas fundamentally
it is not necessary to propagation at all. It
is perfectly true, of course, that in the majority
of animals, and also in many plants, an individual
life begins in the union of two minute elements, the
mother egg-cell and the sperm father-cell. But
this is not the earliest stage, and below these higher
forms we find a great world of life reproducing without
this sex-process by simple separation and growth.
In these unicellular organisms reproduction is known
as asexual, because there are no special germ-cells,
nor is there anything corresponding to fertilisation.
The most common forms are (1) by division into two;
(2) by budding, a modified form of division; (3) by
sporulation, a division into many units.
It is worth while to wait to learn
something of this first stage in the development of
life, for in this way we shall gain a clue as to the
origin of sex and the real purpose it fulfils in the
service of reproduction. In the very simplest
forms of unicellular organisms propagation is effected
at what is known as “the limit of growth”;
when the cell has attained as much volume as its surface
can adequately supply with food, a simple division
of the cell takes place into two halves or daughter
cells, each exactly like the other, which then become
independent and themselves repeat the same rupture
process. But in some slightly more complex cases
differences occur between the two cells into which
the organism divides, as in the slipper animacule,
where one-half goes off with the mouth, while the
other has none. In a short time, however, the
mouthless half forms a mouth, and each half grows
into a replica of the original. We have here
one of the earliest examples of differentiation.
That injured multicellular organisms should be able
by regrowth to repair their loss in an analogous phenomenon;
thus an earth-worm cut by a spade does not necessarily
suffer loss, but the head part grows a tail and the
decapitated portion produces a head; sponges, which
do not normally propagate by division, may be cut
in pieces and bedded out successfully; the arms of
a star-fish, torn asunder by a fisherman, will almost
always result in several perfect star-fish. Similarly
among plants a cut-off portion may readily give rise
to new plants-a potato-tuber is one of
hundreds of instances. This ability to effect
complete repair is one of the powers that life has
lost; it persists as high in the scale as reptiles,
and a lizard is able to regrow an amputated leg.
It is certainly not the least interest
in studying these early forms that one is able to
trace the analogy they bear with the higher forms.
No rigid line can be drawn between the successive stages
of growth. And it should be borne in mind that,
simple as is the life-process in these single-celled
organisms, many of them are highly differentiated
and show great complexity of structure within the narrow
limits of their size. Thus among the protozoa,
the basis of all animal life, we find very definite
and interesting modes of behaviour, such as seeking
light and avoiding it, swimming in a spiral, approaching
certain substances and retreating from others; the
organisms often, indeed, trying one behaviour after
another. If we realise this it becomes easier
to understand how the higher types of life have developed
from these primitive types. Indeed, all the bodies
of the most complex animals-including ourselves-originate
as simple cells, and in the individual history of
each of us divide and multiply just as do the cells
which exist independently; only in multicellular organisms
each cell must be regarded as an individual, modified
to serve a special purpose, one cell differentiated
to start a lineage of nerve cells, another a lineage
of digestive cells, yet another for the reproduction
of the species, and so on, each group of cells taking
on its special use, but the power of division remaining
with the modified cell. Thus a new life is built
up-a child becomes an adult, by multiplication
of these differentiated cells, repeating the original
single-cell development.
Budding, the second, and perhaps the
most usual mode of asexual propagation, may be said
to mark a further step in the development of the reproductive
process. Here the mother-cell, instead of dividing
into two equal parts and at once rupturing, protrudes
a small portion of its substance, which is separated
by a constriction that grows deeper and deeper until
the bulk becomes wholly detached. This small
bud then grows until it attains the size of the parent,
when it, in turn, repeats the same process. This
mode of reproduction is common to the great majority
of plants. In animal life it is not confined to
single-celled organism, but takes place in certain
multicellulars, such as worms, bryozoans, and ascidians;
one very interesting example being the sea-worm (myrianida)
which buds off a whole chain of individuals.
Nearly allied with budding is the
third stage, in which the division is multiple and
rapid within the limited space of the mother-cell.
This is known as spore formation. The cells become
detached, and do not further develop until they have
escaped from the parent. They then increase by
division and growth to form independent individuals.
This spore reproduction is found among certain types
of vegetation; it also occurs in the protozoa.
It is probable that these three stages
of asexual reproduction are not all the steps actually
taken by Nature in the development of the early life-process.
There must have been intermediate steps, perhaps many
such, but the forms in which they occur either have
not persisted, or have not yet been studied. The
feature common to all ordinary forms of asexual multiplication
is that the reproductive process is independent of
sex; what starts the new life is the half, or a liberated
portion of the single parent cell. It will be
readily seen that by this process the offspring are
identical with the parent. Life continues, but
it continues unchanged. Thus the power of growth
is restricted within extremely narrow limits.
Any further development required a new process.
With the life-force pushing in all directions every
possible process would be tried. We are often
met with striking phenomena of adjustments to new
conditions, which in some cases, when found to be
advantageous to the organism, persist. There is,
in fact, abundant evidence that Nature in these early
days of life was making experiments. In pursuance
of this policy it naturally came about that any process
by which the organism gained increased power of growth
had the greater likelihood of survival. The number
of devices in the way of modification of form and
habit to secure advantage is practically infinite;
but there was one principle that was eagerly seized
upon at a very early stage, and, persisting by this
law of advantage, was utilised by all progressive
types as an accessory of success. This was the
principle of fertilisation, which arose in this way
from what would almost seem the chance union of two
cells, at first alike, but afterwards more and more
highly differentiated, and from whose primordial mating
have proceeded by a natural series of ascending steps
all the developed forms of sex.
The ways in which this was brought
about we have now to see. But even at this point
it becomes evident that the true office of sex was
not the first need of securing reproduction-that
had been done already-rather it was the
improving and perfecting of the single-cell process
by introducing variation through the commingling of
the ancestral hereditary elements of two parents,
and, by means of such variations, the production of
new and higher forms of life-in fact, progress
by the mighty dynamic of sex.
As we should expect, the passing from
the sexless mode of reproduction to the definite male
and female types is not sharply defined or abrupt.
Even among many unicellular organisms the process becomes
more elaborate with distinct specialisation of reproductive
elements. In some cases conjugation is observed,
when two individuals coalesce, and each cell and each
nucleus divides into two, and each half unites with
the half of the other to form a new cell. This
is asexual, since the uniting cells are exactly similar,
but the effect would seem to be the strengthening
of the cells by, as it were, introducing new blood.
In somewhat more complex cases these cells do not
part company when they divide, but remain attached
to one another, and form a kind of commonwealth.
Here one can see at once that some cells in a little
group will be less advantageously placed for the absorption
of nourishment than others. By degrees this differentiation
of function brings about differentiation of form,
and cells become modified, in some cases, to a surprising
extent, to serve special purposes. The next advance
is when the uniting cells become somewhat different
in themselves. In the early stages this difference
appears as one of size; a small weakly cell, though
sometimes propagating by union with a similar cell,
in other cases seeks out a larger and more developed
cell, and by uniting with it in mutual nourishment
becomes strong. This may be seen among the protozoa
where we can trace the distinct beginnings of the
male and female elements. A very instructive example
is furnished by the case of volvox, a multicellular
vegative organism of very curious habits. The
cells at first are all alike; they are united by protoplasmic
bridges and form a colony. In favourable environmental
conditions of abundant nutrition this state of affairs
continues, and the colony increases only by multiplication
and without fertilisation. But when the supply
of food is exhausted, or by any cause is checked,
sexual reproduction is resorted to, and this in a
way that illustrates most instructively the differentiation
of the female and male cells. Some of the cells
are seen accumulating nourishment at the expense of
the others and grow larger, and if this continues,
cells which must be regarded as ova, or female cells,
result; while other cells, less advantageously placed
with more competitors struggling to obtain food, grow
smaller and gradually change their character, becoming,
in fact, males. In some cases distinct colonies
may in this way arise, some composed entirely of the
large well-nourished cells, and others of small hungry
cells, and may be recognised as completely female
or male colonies.
We are now in a position to gain a
clue to the difficult problem of the origin of the
sexes. It would be easy as well as instructive
to accumulate examples. I am tempted to linger
over the life-histories of these early organisms that
are so full of suggestion; but the case I have selected-the
volvox-really answers the question.
Sex here is dependent on, and would seem to have arisen
through, differences in environmental conditions.
We find the well-nourished, larger, and usually more
quiescent cell is the female, the hungrier and more
mobile cell the male; the one concerned with storing
energy, the other with consuming it, the one building
up, the other breaking down; or expressed in biological
formula, the female cell is predominantly anabolic,
that of the male predominantly katabolic. Thus
we find that the male, through a want of nutrition,
was carried developmentally away from the well-fed
female cell, which it was bound to seek and unite
with to continue life. This relation between
the food supply and the sexes is found persisting in
higher forms, and, in this connection, the well-known
experiments of Young on tadpoles and of Siebald on
wasps may be cited. By increasing the nutrition
of tadpoles the percentage of females was raised from
the normal of about fifty per cent. to ninety, while
similarly among wasps the number of females was found
to depend on warmth and food supply, and to decrease
as these diminished. Mention also may be made
of the plant-lice, or aphides, which infest our rose-bushes
and other plants, which, during the summer months,
when conditions are favourable, produce generation
after generation of females, but on the advent of
autumn, with its cold and scarcity of food, males appear
and sexual reproduction takes place. Similarly
brine-shrimps when living under favourable conditions
produce females, but when the environment is less
favourable males as well are found. Another significant
fact is the simple and well-known one that within
the first eight days of larval life the additions
of food will determine the striking and functional
differences between the workers and queen-bee.
Among the higher animals the difficulties of proving
the influence of environment upon sex are, of course,
much greater. There are, however, many facts
which point to a persistence of this fundamental differentiation.
Among these it is sufficient to mention the experiments
of stock-breeders, which show that good conditions
tend to produce females; and the testimony of furriers
that rich regions yield more furs from females, and
poor regions more from males. Even when we reach
the human species facts are not wanting to suggest
a similar condition. It is usual in times of
war and famine for more boys to be born; also more
boys are born in the country than in cities, possibly
because the city diet is richer, especially in meat.
Similarly among poor families the percentage of boys
is higher than in well-to-do families. And although
such evidence is not conclusive and must be accepted
with great caution, it seems safe to say that the facts-of
which I have given a few only of the most common-are
sufficient to suggest that the relation among the
lower forms of life persists up to the human species,
and that the female is the result of surplus nutrition
and the male of scarcity.
This is sufficient for our present
purpose; all other questions and theories brought
forward regarding the determination and conditions
of the sexes are outside our purpose. Those who
will survey the evidence in detail will find ample
confirmation of the point of view I wish to make clear.
(1) All species are invented and tolerated by Nature
for parenthood and its service; (2) the demands laid
upon the female by the part required from her are
heavier than those needed for the part fulfilled by
the male. The female it is who is mainly responsible
to the race. And for this reason the progress
of the world of life has always rested upon and been
determined by the female half of life. What I
wish to establish now is that the male developed after
and, as it were, from the female. The female
led, and the male followed her in the evolution of
life.