Encyclopaedia Britannica > Volume 21, ROT-Siam

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female offspring appear in increasing majority. This view
has been confirmed by Goehlert, Boulanger, Legoyt, and
others; some breeders of horses, cattle, and pigeons have
also accepted it. Other breeders, however, deny it alto¬
gether ; moreover, the recent statistics of Stieda and of
Berner (taken independently from Alsace-Lorraine and
Scandinavia) seem to stand in irreconcilable contradiction.
At any rate at present we do not seem justified in ascribing
greater importance to the relative age of parents than as a
secondary factor, which may probably take its place among
those causes influencing nourishment discussed below.
That good nourishment appears to produce a distinct
preponderance of females is perhaps the single result
which can at present be regarded as clearly proven and
generally accepted. Yet it would be too much to say that
unanimity is even here complete; thus, among plants, the
experiments of Girou (1823), Haberlandt (1869), and
others gave no certain result; those of Heyer (1883)
have led him to dispute the validity of the generalization
altogether, while Haberlandt (1877) brought evidence for
regarding the excess of females as largely due to the greater
mortality of the males. The investigations of agricultural
observers, especially Meehan (1878), which are essentially
corroborated by Busing (1883), however, leave little doubt
that abundant moisture and nourishment tend to produce
females. Some of Meehan’s points are extremely instruc¬
tive. Thus old branches of Conifers overgrown and shaded
by younger ones produce only male inflorescences, a fact
which may be taken in connexion with Sadebeck’s obser¬
vation that some fern prothallia, under unfavourable con¬
ditions, can still form antheridia but not archegonia. The
formation of female flowers on male heads of maize is
ascribed by Knop to better nutrition consequent on abund¬
ant moisture, The only seriously contradictory observa¬
tions are thus those of Heyer, and it is therefore reassuring
when a detailed scrutiny of his paper shows his ill-con-
ducted experiments (which land him in the conclusion that
the organism is not modifiable by its environment at all)
to be largely capable of a reversed interpretation. The
agency of temperature is also of considerable importance.
Thus Meehan finds that the male plants of hazel grow
more actively in heat than the female, and Ascherson
states that Stratiotes aloides bears only female flowers
north of 52° lat., and from 50° southwards only male ones.
Other instances might be given.
Passing to the animal kingdom we find the case of
insects peculiarly clear ; thus Mrs Treat showed that if
caterpillars were starved before entering the chrysalis
state the resultant butterflies or moths were males, while
others of the same brood highly nourished came out
females. Gentry too has shown for moths that innutri-
tious or diseased food produced males; hence perhaps a
partial explanation of the excess of male insects in autumn,
although temperature is probably more important. The
recent experiments of Yung on tadpoles are also very
conclusive. Thus he raised the percentage of females in
one brood from 56 in those unfed to 78 in those fed with
beef, and in another supply from 61 to 81 per cent, by
feeding with fish; while, when the especially nutritious
flesh of frogs was supplied, the percentage rose from 54
to 92. Among mammals the difficulties of proof are
greater, but evidence is by no means wanting. Thus an
important experiment was long ago made by Girou, who
divided a flock of 300 ewes into equal parts, of which the
one half were extremely well fed and served by two young
rams, while the other was served by two mature rams and
poorly fed. The proportion of ewe lambs in the two cases
was respectively 60 and 40 per cent. Busing also states
that it is usually the heavier ewes which bring forth ewe
lambs.
Nor does sex in the human species appear to be
independent of differences of nutrition. After a cholera
epidemic or a war more boys are said to be born, and
Busing also points out that in females with small placenta
and little menstruation more boys are found, and even
affirms that the number of male children varies with the
rise in prices. In towns and in prosperous families there
are also more females, while males are more numerous in
the country and among the poor. The influence of tem¬
perature is also marked : more males are born during the
colder months, a fact noted also by Schlechter for horses.
The best known and probably still most influential
theory is that systematized by Girou and known as that of
“ comparative vigour.” This makes sex of offspring depend
on that of the more vigorous parent. But to this view
there are serious difficulties : thus consumptive mothers
produce a great excess of daughters, not sons as might be
expected from the superior health of the father. Still less
weight can be attached to that form of the hypothesis
which would make sex follow “genital superiority” or
“ relative ardency ” alone. Any new theory has thus to
reconcile the arguments in favour of each of the preceding
views, and meet the difficulties which beset all. As
Starkweather puts it, it must at once account for such
facts as “ the preponderance of male births in Europe, of
females among mulattos and other hybrid races, as also
among polygamous animals, and for the equality among
other animals. More especially it must suggest some
principle of self-adjustment by which not only is the
balance of the sexes nearly preserved on the whole, but by
which also in cases of special disturbance the balance
tends to readjust itself.” Starkweather proceeds to
attempt this, and his argument may be briefly summarized.
While few maintain any essential equality of the sexes,
and still fewer any superiority of the female, the weight of
authority has been from the earliest times in favour of the
doctrine of male superiority. From the earliest ages
philosophers have contended that woman is but an unde¬
veloped man ; Barwin’s theory of sexual selection presup¬
poses a superiority in the male line and entailed on that
sex; for Spencer the development of woman is early
arrested by procreative functions : in short, Barwin’s man
is as it were an evolved woman, and Spencer’s woman an
arrested man. On such grounds we have a number of
theories of sex. Hough thinks males are born when the
system is at its best, more females when occupied in
growth, reparation, or disease. So, too, Tiedman and
others regard every embryo as originally female and
remaining female if errested, while Yelpau conversely
regards embryos as all naturally male, but frequently
degenerating to the female state. Starkweather points out
some of the difficulties to the view of female inferiority,
and lays it down as the foundation of his work that
“neither sex is physically the superior, but both are essen¬
tially equal in a physiological sense.” But, while this is
true of the average, there are many grades of individual
differences and deficiencies in detail, involving a greater or
less degree of superiority in one or other of every pair.
Starkweather’s theory then is “ that sex is determined by
the superior parent, also that the superior parent produces
the opposite sex.” The arguments adduced in favour of
this view, however, are scarcely worthy of it, since, save a
chapter of pseudo-physiological discussion of vital forces
and polarities, of superiority,—nervous, electrical, &c.,—
they rest mainly on the vague and shifting grounds of
physiognomy and temperament. And when superiority is
analysed into its factors,—cerebral development and activ¬
ity, temperament, state of health, of nutrition, &c.,—soon
we find under the appearance of simplicity a law has been
obtained not by discovering any real unity under the many