═══════════════════════════════════╤═══════════════════════════════════
OF EVERY 100 WOMEN WHO MARRY │ THERE BECOME MOTHERS
───────────────────────────────────┼─────────────────┬─────────────────
„ │ In the 1st year │In the 2d year of
│of married life. │ married life.
───────────────────────────────────┼─────────────────┼─────────────────
Between the ages of 15 and 20 years│ 13.71│ 43.70
Between the ages of 20 and 25 years│ 18.48│ 90.51
Between the ages of 25 and 30 years│ 12.41│ 75.80
Between the ages of 30 and 35 years│ 11.44│ 62.93
Between the ages of 35 and 40 years│ 9.27│ 40.97
═══════════════════════════════════╧═════════════════╧═════════════════
_Sadler_ examined the relationship between the age at which marriage was
contracted and the number of offspring in the case of the wives of
English peers. He obtained the following results:
Age at marriage. Births per marriage.
12 to 16 years 4.40
16 to 20 years 4.63
20 to 24 years 5.21
24 to 28 years 5.43
From exact statistical data of births in the Scandinavian countries of
Europe (Denmark, Sweden and Norway), _Goehlert_ compiled the following
table, showing the percentages of fertility at various ages:
═════════════════╤══════════════════════════╤══════════════════════════
AGES. │ MARRIED WOMEN. │ UNMARRIED WOMEN.
─────────────────┼────────┬────────┬────────┼────────┬────────┬────────
„ │Denmark.│Sweden. │Norway. │Denmark.│Sweden. │Norway.
─────────────────┼────────┼────────┼────────┼────────┼────────┼────────
Under 20 years. │ 1.0│ 1.0│ 0.7│ 9.1│ 7.0│ 4.9
From 20 to 25 │ 13.9│ 12.8│ 11.9│ 43.9│ 35.1│ 37.0
years. │ │ │ │ │ │
From 25 to 30 │ 26.5│ 24.7│ 24.7│ 28.1│ 27.9│ 32.4
years. │ │ │ │ │ │
From 30 to 35 │ 26.7│ 26.1│ 25.3│ 11.4│ 16.8│ 14.9
years. │ │ │ │ │ │
From 35 to 40 │ 21.0│ 21.6│ 21.3│ 5.4│ 9.0│ 7.1
years. │ │ │ │ │ │
─────────────────┼────────┼────────┼────────┼────────┼────────┼────────
From 40 to 45 │ 9.9│ 12.0│ 13.0│ } 2.1│ 4.2│ 3.7
years. │ │ │ │ │ │
Over 45 years. │ 1.1│ 1.8│ 3.1│ „ │ „ │ „
─────────────────┴────────┴────────┴────────┴────────┴────────┴────────
From this table it appears that the fertility of married women increases
steadily up to the age of 35 years, but after this age it begins to
decline. What a marked influence the age at marriage has upon fertility
is shown by the comparison of the figures relating to married women with
those relating to unmarried women; the fertility of unmarried mothers
attains its maximum at the ages of 20 to 25 years. In the countries
under consideration the average age of women at the time of marriage is
25 to 27 years.
In order to obtain a still clearer picture of the fertility of women in
relation to age, _Goehlert_ has combined the figures relating to the
married and the unmarried, and then calculated the percentages, with the
following results:
════════════════════════════════════════════╤══════════════════════════
AGES. │ MARRIED AND UNMARRIED
│ WOMEN.
────────────────────────────────────────────┼────────┬────────┬────────
„ │Denmark.│Sweden. │Norway.
────────────────────────────────────────────┼────────┼────────┼────────
Under 20 years. │ 1.7│ 1.6│ 1.1
From 20 to 25 years. │ 16.6│ 15.1│ 14.1
From 25 to 30 year │ 26.6│ 25.0│ 25.3
From 30 to 35 years. │ 25.3│ 25.1│ 24.4
From 35 to 40 years. │ 19.6│ 20.4│ 20.0
From 40 to 45 years. │ 9.2│ 11.2│ 12.2
────────────────────────────────────────────┼────────┼────────┼────────
From 45 to 50 years. │ } 1.0│ 1.6│ 2.9
Over 50 years. │ „ │ „ │ „
────────────────────────────────────────────┴────────┴────────┴────────
If, finally, we combine into a single table the figures relating to all
three of these countries, we obtain the following results:
Under 20 years 1.5%
From 20 to 25 years 15.3%
From 25 to 30 years 25.6%
From 30 to 35 years 24.9%
From 35 to 40 years 20.0%
From 40 to 45 years 10.9%
Over 45 years 1.8%
From these figures it appears that the maximum fertility of married
women is attained, in Denmark at the age of 31, in Norway at the age of
31.7, and in Sweden at the age of 32 years. In the case of unmarried
women, the maximum fertility is at the ages of 24 to 26 years. In the
Austrian Empire, the maximum fertility of women is attained at about the
age of 30 years; in England it is attained between the ages of 20 and 25
years.
Divergent results as regards the fertility of married women at different
ages were obtained by _Goehlert_ from the examination of 5,290 cases
from the reigning families of Europe. In the favourable position as
regards means of subsistence occupied by the members of these families,
marriage naturally occurs, in most cases, much earlier in life, the mean
age at marriage being between 19 and 22 years—the youngest mother (in
the Capet dynasty) was only 13 years of age—and for this reason the
figures relating to the younger age-classes are larger than in the
previous tables. But as a result of this, the reproductive capacity also
undergoes an earlier extinction, so that of these women, not one gave
birth to a child when she was over 50 years of age. _Goehlert_ gives the
following table, compiled from these 5,290 instances:
Under 20 years 8.8%
From 20 to 25 years 25.4%
From 25 to 30 years 29.4%
From 30 to 35 years 21.6%
From 35 to 40 years 11.5%
Over 40 years 3.3%
In these cases the maximum fertility was obtained at the age of 27.
The physiological fertility of women is much more clearly manifested
when we compare the fertility of women who have been married a few years
only, with the fertility of women in the later years of married life. In
the earlier period, the effective fertility more nearly approaches the
physiological fertility, because at this time the various influences by
means of which fertility is later so greatly diminished have not yet
come into operation. In this connection the following data, published by
_Körösi_, regarding the percentage fertility of recently married women,
and that of married women in general, will be found of interest:
═══════════════════════╤═══════════════════════╤═══════════════════════
│Recently-married women.│ All married women.
───────────────────────┼───────────────────────┼───────────────────────
At ages 20 to 35 years.│ 32.9%│ 20.6%
At ages 35 to 40 years.│ 32.7%│ 14.7%
At ages 40 to 45 years.│ 21.4%│ 5.9%
═══════════════════════╧═══════════════════════╧═══════════════════════
Inasmuch as we learn from this table that in the case of women aged 40
and upward, the newly married exhibit a fertility of four times as great
as that of married women in general, in whom pregnancy has already
become rare, we can infer the influence upon fertility of abstinence and
of artificial measures for the prevention of conception.
On the average, the maximum fertility of woman, that is, the maximum
of effective fertility, is attained at the age of 18 to 20 years.
Extreme youthfulness, and also the opposite condition, too advanced an
age, when marriage is entered on, impair a woman’s fertility; whereas
the conditions most favourable to fertility are that, at the time of
marriage, the uterus should have attained its fullest development, and
the ovaries also should be completely mature; this is not usually the
case at puberty, but rather at the age of 20, 21, or 22 years. In
Austria-Hungary, of 100 marriages in which the wife’s age at marriage
was less than 18 years, the average offspring in the course of a
single year were 36 to 38 children; in the case of 100 marriages in
which the wife’s age at marriage was 18 to 20 years, the average
offspring in a year were 40; this being the maximum fertility, the
number of offspring in a year per hundred marriages (i. e., the
percentage fertility), now undergoes a regular decline as the wife’s
age at marriage increases; at an age of 25, the percentage fertility
is 32; at the age of 30 years, the fertility is 24%; at the age of 35,
17%; at the age of 40 years barely 10%; at the age of 45, 7%; at ages
45 to 50, 0.1%. Thus, from the last figure, we see that of a thousand
women marrying at the age of 50 years, one only gives birth to a
child. Men obtain their maximum fertility (i. e., procreative
capacity) at the age of 25 or 26 years; at this age their fertility
amounts to 35% (that is, of 100 marriages at this age, 35 children
will on the average be born within a single year); at the age of 35
years, the percentage fertility of men falls to 23; at the age of 45
years, it is 9½%; at 55, 2.2%; at 65, ½% (_Körösi-Blaschko_).
Whereas hitherto we have considered only the monogenous fertility of
married women, we must remember that the figures relating to their
biogenous fertility are also of interest—that is to say, the changes
which a woman’s fertility experiences in married life in respect of the
peculiarities of her husband; and of these peculiarities, the easiest to
make the object of statistical investigation is the husband’s age. The
age of the husband exercises an important influence upon the fertility
of the wife, as is proved by the following figures published by
_Körösi_:
════════════════════════════╤════════════════════════════════════════════
AGE OF THE FATHER. │ AGE OF THE MOTHER.
────────────────────────────┼──────────────┬──────────────┬──────────────
„ │ 25 years. │ 30 years. │ 35 years.
────────────────────────────┼──────────────┼──────────────┼──────────────
25 to 30 years │ 35.6%│ 25.0%│ 21.2%
30 to 35 years │ 31.2%│ 23.6%│ 19.9%
35 to 40 years │ 27.5%│ 21.8%│ 19.4%
40 to 45 years │ │ 16.7%│ 14.0%
45 to 50 years │ │ 14.4%│ 10.9%
50 to 55 years │ │ │ 10.9%
════════════════════════════╧══════════════╧══════════════╧══════════════
Also:
══════════════╤═══════════════════════════════════════════════════════════
AGE OF THE │ AGE OF THE FATHER.
MOTHER. │
──────────────┼──────────────┬──────────────┬──────────────┬──────────────
„ │ 25 years. │ 35 years. │ 45 years. │ 55 years.
──────────────┼──────────────┼──────────────┼──────────────┼──────────────
Under 20 years│ 49.1%│ │ │
20 to 25 years│ 43.0%│ 31.3%│ 16.0%│
25 to 30 years│ 30.8%│ 27.3%│ 18.5%│
30 to 35 years│ 33.5%│ 23.7%│ 14.4%│ 8.1%
35 to 40 years│ │ 18.9%│ 11.8%│ 6.7%
40 to 45 years│ │ 6.6%│ 6.1%│ 3.0%
══════════════╧══════════════╧══════════════╧══════════════╧══════════════
We learn from these figures that the maximum fertility is exhibited by a
woman 18 years of age, when married to a man 25 years of age; less
fertile is a woman 25 to 30 years of age married to a man 28 years of
age; still less fertile is a woman 35 years of age married to a man 29
years of age. Neither the age of the mother alone, nor that of the
father alone, is determinative of the fertility of the marriage, for the
fertility of young wives married to elderly husbands is quite different
from that of young wives married to young husbands. Very various
age-combinations are possible, and each exhibits an average fertility
peculiar to itself.
We can also regard the question from the standpoint of the _difference_
between the ages of husband and wife respectively. In this connection,
_Körösi_ is led by his tables to the conclusion that wives between the
ages of 18 and 20 years attain their maximum fertility when married to
men 7 years older than themselves; women of 25 years when married to men
3 years older than themselves; women of 29 years when married to men of
the same age; women of 30 years and upward attain their maximum
fertility only when married to men younger than themselves. Men, on the
contrary, always attain their maximum fertility when married to women
younger than themselves. The age of maximum fertility differs in the two
sexes, and those marriages will be most fruitful in which husband and
wife are each of the age most favorable to fertility. This will be the
case when the age of the wife is 18 to 20 years, and that of the husband
24 to 26 or perhaps 29 years.
In connection with the question of fertility, we have also to take into
consideration the vitality of the children born, that is, what
proportion of those born survive. According to _Körösi’s_ interesting
papers regarding the fertility of the inhabitants of Buda-Pesth, we
learn that for every 100 marriages which have persisted for thirty years
and upward, there were born, on the average, 539 children, of whom
during this period 241 died, so that the percentage of survivals was
55.28. Parents who have lost one only of several children must,
therefore, regard themselves as exceptionally favoured by fortune.
Social position, occupation, and religion, have, according to the
last-quoted author, a notable influence on fertility. His investigations
showed that the Roman Catholics and the Jews exhibited the greatest
fertility; among the Catholics there were 541 children, and among the
Jews 557 children, per 100 marriages. Amongst 100 Protestant families,
on the other hand, only 479 children had been born. It will be seen that
the theory of the comparatively enormous fertility of the Jewish race is
not supported by these statistics. The Jews do, however, exhibit a
greater power of rearing children, for among them the marriages of more
than 30 years’ duration had 61⅔ % of the children still living; among
the Protestants 57¾% survived; and among the Catholics only 52–⅗%. It
thus appears that the surviving offspring per 100 marriages of 30 years’
duration were, among the Catholics 278, among the Protestants 252, and
among the Jews 349.
The question whether, and to what extent, the age of the parents has an
influence on the vitality of the children, is answered by _Körösi’s_
mortality statistics in the sense that mothers below 20 years of age
give birth to a larger proportion of children deficient in vital power.
Where the mothers had married at the age of 16, the mortality of their
offspring was, among Catholics 43%, among Jews 33%; married at 17,
Catholic mortality 44%, Jewish 30%; married at 18, Catholic mortality
42%, Jewish 32%; married at 19, Catholic mortality 41%, Jewish 29%;
married at 20, Catholic mortality 40%, Jewish 26%. Of the children whose
fathers had married at the age of 24, 32% had died; of those whose
fathers had married at 23, 37% had died; of those whose fathers had
married at 20, 42% had died; and of those whose fathers had married
before 20, actually 44% had died. It thus appears that the children
alike of very young mothers and of very young fathers have a lessened
chance of survival.
Inasmuch as the fertility of the wife is a product of two factors, her
own peculiar fertility, and that of the procreating male, the question
of the fertility of women cannot be accurately treated independently of
this second consideration; hereby, however, is introduced a multiplicity
of obscure combinations, by which the value of all the statistical data
of fertility in women is seriously impaired.
These data give as the measure of fertility, the number of children per
marriage actually brought up, embracing fruitful marriages, sterile
marriages, and those not yet fruitful. In Berlin, in Copenhagen, and in
Buda-Pesth, the average thus attained was slightly less than three
births to each family, whilst the number of children actually living
averaged two per family. A more accurate representation of fertility is
obtained by ascertaining the number of children born, and the number of
children living in relation to the duration of marriages reckoned in
years, that is beginning with marriages of one year’s duration, and
proceeding year by year to the highest recorded duration of marriage. In
this way interesting statistics have been obtained; for example, one who
has completed thirty years of married life may count on the average that
five or six children will have been born to him, but may also reckon on
having buried two or three at least of these. (_Körösi._)
Fertility is, as many facts indicate, also dependent on nutrition. A
distinct proof, says _Spencer_, writing on the “Coincidence between high
Nutrition and Genesis,” that abundant nutriment increases the number of
births, and vice versa, is found among the mammalia; compare, for
instance, the litter of the dog with that of the wolf and the fox.
Whilst the dog’s litter numbers 6 to 14, that of the wolf numbers 5 to
7, that of the fox 4 to 6. The wild cat gives birth to 4 or 5 kittens
once a year, the domesticated cat to 5 or 6, twice or thrice annually.
The most remarkable contrast, in this respect, exists between the wild
and the domesticated breeds of swine. The wild sow gives birth once a
year to a litter of 4, 8, or 10 pigs (the number increasing in
successive litters); the domesticated sow has often as many as 17 in a
single litter, whilst in two years five litters, each numbering 10 pigs,
are commonly born.
_Darwin_ also draws attention to the fact that animals under
domestication, being fed more abundantly and regularly than their wild
allies, procreate at shorter intervals and are markedly more fertile
than the latter. He states that the wild rabbit has four litters
annually, each numbering 4 to 8 young; whereas the tame rabbit
reproduces its kind six to seven times annually, and gives birth to
litters numbering 4 to 11. Among birds, analogous phenomena are
observed. The wild duck, for instance, lays 5 to 10 eggs in the course
of the year, whereas the tame duck lays from 80 to 100; the wild grey
goose lays 5 to 8 eggs, the domesticated goose 13 to 18.
It must be added that this exceptional fertility is manifested in
animals that are quite inactive in comparison with their wild allies;
not only are they richly fed, but they get their food without working
for it. Moreover, it is easy to observe that among the domesticated
mammals the well-fed are more fertile than the ill-fed.
That in the human species also, fertility is influenced to a notable
degree by nutritive conditions, is shown by statistical investigation.
After years distinguished by an exceptionally good harvest the number of
children born is considerably greater than in normal conditions; whereas
after a famine the opposite is observed. _Malthus’s_ law of population
states, _inter alia_, that the population increases when the amount of
available nutriment increases, that is, that favourable nutritive
conditions cause an increase, that unfavourable nutritive conditions
cause a decrease, of population. Hardships and exhausting occupations
diminish the fertility of women. The remarkable fertility of the Kaffirs
is referred to the fact that this people, possessing large herds of
cattle, lead a life comparatively free from care; it is no less true
that the Boer women, who lead a life of well-fed leisure, have very
large families; whereas the Hottentot women, poor, ill-nourished, and
hard working, seldom bear more than three children.
Generally speaking, it may be said that fertility of the soil, in
connection with an easily gained livelihood, favours also human
fertility, notwithstanding the fact that certain statistical data seem
to conflict with this proposition. _Sadler_, for instance, concludes
that an increase in the price of the necessaries of life does not _per
se_ check fertility, but, indeed, rather increases it; he considers that
the apparent decline in fertility is due to the fact that the number of
marriages diminishes, owing to the rise in prices. We must, however,
point out, that an increase in price of the necessaries of life is often
associated with a rise in wages, and is therefore not necessarily
identified with deficient nutrition; when, however, such a rise in
prices leads to actual want, a limitation of fertility will certainly
result; this has been proved by _Legoyt_ and _Villermé_ with regard to
failure of the crops. Famine and disease lower the number of births; a
less severe deficiency of nutriment often lowers only the quality of
those born. _Malthus_ was of opinion that the population of a country at
any time was related to the quantity of nutriment produced or imported
therein, on the one hand, and, on the other, to the liberality with
which this nutriment was distributed to the individual. In countries
where corn forms the principal crop, we find a thicker population than
in pasture lands; and where rice is the principal crop, the population
is even more abundant than it is in corn growing countries.
Passing to the consideration of the individual nutritive elements, we
find that these also influence fertility. Above all, it has been proved
that alcohol notably diminishes the fertility of women. _Lippich_ states
that of 100 women in Kärnten and Krain suffering from chronic
alcoholism, 28.3 were barren. In England, where the abuse of alcoholic
beverages is also very frequently observed in women, the same phenomenon
has been noted. _Matthews Duncan_ held that alcohol exercised a specific
deleterious influence on fertility. Moreover, in addition to the
constitutional disturbances produced by the abuse of alcohol, this
beverage also exercises a well-known pathogenetic influence upon the
female reproductive organs; with especial frequency, chronic oöphoritis
may be shown to depend on this exciting cause.
A diet consisting mainly of fish is known to increase the sexual
impulse, and is said also to increase fertility. Further, a diet
consisting mainly of potatoes or rice is said to favour reproduction;
compare, for instance, the fertility of the Hindoos, who abstain
entirely from animal food, and of the Chinese, who live chiefly on rice.
_Davy_ maintained that the women of races living chiefly on fish were
handsomer and more fertile than others: and _Montesquieu_ suggested that
there was an association between the abundant population of sea-ports
and also of Japan and China, and the large quantity of fish consumed in
those places. On the other hand, a diet consisting chiefly of meat is
said to have an unfavourable influence in this direction; in support of
this view it is pointed out that races living by the chase, and living
therefore almost entirely on meat, have very small families. This
generalization is invalidated by the fact that Englishwomen, who eat far
more meat than the women of the Latin races, are nevertheless
distinguished by their great fertility.
In his “History of Civilisation in England” _Buckle_ writes: “The
population of a country, although influenced by many other conditions,
unquestionably rises and falls in proportion as the supply of nutriment
is abundant or the reverse.” _Herbert Spencer_ also states that “every
increment in the supply of nutriment is followed by an increment in
fertility.”
It must not be forgotten that, in addition to the more or less abundant
supply of nutriment, there are always other influences affecting
fertility; the general mode of life, race, climatic conditions, etc.,
may, in various ways, co-operate with or countervail the influence of
nutritive conditions. If, with the best possible supply of nutriment,
there is associated a luxurious and enervating mode of life, the abuse
of alcohol, severe intellectual exertion, or sexual excesses, the
general result will be a diminution in fertility. And it is easy to
understand why _Cros_, although perhaps with little justification, goes
so far as to regard easy circumstances as an active cause of
depopulation. “It is the poor,” he writes, “and the less wealthy
departments of France, in which we find the most children.” In
estimating fertility, however, we must never fail to take into
consideration the more extensive employment of means for the prevention
of pregnancy among the upper classes of society.
To a certain extent we can trace the influence of climate and of season
upon fertility. Heat appears to favour fertility; _Haycraft’s_ figures
for the eight largest towns of Scotland show clearly how the number of
conceptions rises and falls _pari passu_ with the temperature. Lower
animals also, when brought from a colder to a warmer neighbourhood,
exhibit an earlier and more frequently recurring “heat.” In Europe,
however, the Northern races appear more fertile than those of the south.
Of the seasons, spring is the one especially favourable to fertility.
_Quetelet_, who proves by numerous statistical data that the maximum of
conceptions occurs in May, attributes this fact to a general increase in
the vital forces occurring in spring, after the cold of winter.
_Villermé_, however, goes back to the older explanation, that the
increase in the number of conceptions in May and June is due to social
and economic conditions. The return of spring, especially the end of
spring and the beginning of summer, a time of year in which the means of
subsistence are provided in exceptional quantity, and of especially good
quality, the season also of festivals and social reunion, when the two
sexes are brought into more intimate contact and when the majority of
marriages occur—these are the conditions associated with the season of
greatest fertility. The figures of _Wappaeus_ also confirm the influence
of spring in favouring fertility. He found, however, that there were two
seasons of maximal fertility. The first at the end of spring and the
beginning of summer; the second in winter, especially in December.
Mid-winter is for most people a period of domestic amusement and
relaxation, one of exceptionally good nutrition, and of social reunion;
the spring increase in fertility is a part of the awakening and increase
of the reproductive forces of nature at large, which recurs every
spring-time.
Every marked and sudden change in the mode of life has an unfavourable
influence on fertility. _Darwin_ reports that mares who have for some
time been stall-fed with dry fodder and are then put out to grass are at
first infertile after the change. Europeans going to reside in the
tropics experience a notable decline in fertility as a result of the
change of climate. According to _Virchow_, the fertility of European
women who become acclimatized in the tropics declines very gradually,
but in the course of a few generations is almost completely annulled.
The marriage of near kin is believed also to diminish fertility. As
regards inbreeding in the lower animals, it is well known that when
nearly related animals copulate, the number of the offspring is below
the average. _Nathusius_ paired a sow with its own uncle, the boar
having proved productive in intercourse with other sows; the litter
numbered five to six only. This sow, which belonged to the great
Yorkshire race, was then paired with a small black boar, which in
intercourse with sows of its own variety had procreated litters
numbering six or seven; as a result of her first pairing with the black
boar, the sow cast a litter numbering twenty-one whilst the second
attempt produced a litter of eighteen. Similar results were obtained by
_Crampe_, in his experiments in the inbreeding of rats.
Some authorities declare that the results of inbreeding are similar in
the human species, that the marriages of near kin are less fruitful than
the average. _Darwin_ writes in this connection: “With regard to human
beings, the question whether breeding in-and-in is also deleterious,
will probably never receive a direct answer, for man reproduces his kind
so very slowly, and cannot be made the object of experiment. The very
general disinclination of nearly all races to the marriage of near kin,
which has existed from the very earliest times, is of weight in relation
to this question. Indeed we appear almost justified in applying to the
human race the experience gained by experiment on the higher mammals.”
_Darwin’s_ assumption regarding the effect upon fertility of the
marriage of near kin in the human species, cannot, however, be accepted
without qualification. In ancient times there was no uniformity of
opinion on this topic. It is well known that among the Phœnicians, a son
might marry his mother, and a father his daughter; and among the ancient
Arabs it was the legal duty of the son to marry his widowed mother.
Moses, on the contrary, forbade marriages between parents and children,
between brothers and sisters, also marriage with a father’s sister, with
a wife’s mother, and with an uncle’s widow.
_Darwin_ considered that the marriage of first cousins was not
unfavourable to fertility. Of 97 such marriages, 14 were sterile, whilst
of 217 marriages of those not akin, 35 were sterile; the percentage in
both cases being almost identical. _Mantegazza_, who regards kinship in
marriage as unfavourable to fertility, found nevertheless that among 512
marriages of near kin, only 8 to 9% were sterile. It is widely believed
that the dying out of many aristocratic families is dependent on the
inbreeding so common in this class—but it must be admitted that
scientific evidence in support of this belief is lacking. Incest in the
human species may certainly result in fertilization. Among the Jews,
marriages of near kin are very common, and often prove extremely
fruitful.
_Göhlert_ made a statistical investigation of the fertility of the
reigning families of Europe, in order to throw light on this question.
In the Capet dynasty, 118 marriages of near kin took place, and of these
41 were sterile; in the Wettin dynasty (Saxony), there were 28 such
marriages, of which 7 were sterile, and 1 produced one child only; in
the Wittelsbach dynasty (Bavaria), 29 such marriages, of which 9 were
sterile, and 3 produced only one child each. Thus of 175 marriages of
near kin, 57, or 32.6% remained sterile. Further, in the
Habsburg-Lothringen dynasty, of 110 marriages, 25 were marriages of near
kin, and of these 33% remained sterile.
It has been assumed since the days of antiquity that temperament and
constitution exercise some influence on fertility. _Hippocrates_,
_Soranus_, and _Diokles_, are among the ancient authors who refer to
this matter. _Soranus_ says very justly: “Since most marriages are
contracted, not from love, but for the procreation of children, it is
irrational, when choosing a wife, to have regard, not to her probable
fruitfulness, but instead of this to the social position and the wealth
of her parents.”
It would appear that a certain dissimilarity in physical constitution
and temperament between husband and wife is favourable to the fertility
of the marriage. For instance, a vivacious, dark husband, and a
lethargic, fair wife, are better suited to one another than a husband
and wife both extremely active, or both of extremely phlegmatic
temperament.
_Toussaint Loua_ published the following figures regarding the fertility
of the women of the various countries of Europe:
══════════════╤═════════════╤═════════════════════════════════════════
│ Number of │
COUNTRY. │ births per │FERTILITY OF WOMEN BETWEEN THE AGES OF 15
│ hundred │ AND 45 YEARS.
│inhabitants. │
──────────────┼─────────────┼─────────────┬─────────────┬─────────────
„ │ „ │ Married. │ Unmarried. │ Average.
──────────────┼─────────────┼─────────────┼─────────────┼─────────────
Hungary │ 4.94│ │ │ 17.8
Russia │ 4.12│ │ │ 20.5
Austria │ 3.93│ │ │ 16.4
Germany │ 3.77│ 34.8│ 2.9│ 17.7
Italy │ 3.67│ 28.8│ 2.4│ 16.1
Holland │ 3.67│ 35.3│ 1.0│ 16.0
Finland │ 3.63│ │ │ 15.8
England │ 3.58│ 29.7│ 1.6│ 15.5
Scotland │ 3.53│ 32.8│ 2.5│ 15.8
Belgium │ 3.25│ 33.7│ 1.8│ 14.8
Denmark │ 3.12│ 28.5│ 2.8│ 14.4
Roumania │ 3.12│ │ │ 13.5
Norway │ 3.10│ 29.3│ 2.2│ 14.0
Sweden │ 3.05│ 29.1│ 2.5│ 13.7
Switzerland │ 3.04│ 29.7│ 1.1│ 13.1
Greece │ 2.96│ │ │ 13.2
Ireland │ 2.69│ 29.8│ 0.5│ 12.3
France │ 2.63│ 20.3│ 1.8│ 11.6
══════════════╧═════════════╧═════════════╧═════════════╧═════════════
In towns, conjugal fertility is less, extra-conjugal fertility greater,
than in the country. An increase in factory labour gives rise to an
increase in the population, but to a decline in the vitality of the
offspring; that is to say, it causes a quantitative increase, and a
qualitative decrease, in fertility. An increase in agricultural labour
has precisely the opposite effect. The influence of war upon fertility
is unfavourable both quantitatively, and qualitatively. According to
_Tschouriloff_, the introduction of universal military service, by
withdrawing for a time all the most vigorous men from domestic life,
tends to diminish fertility. Extensive emigration from a country in
which the soil is fertile, and where the vital conditions are generally
favourable, is stated by _Bertillon_ to cause an increased fertility in
the mother country; he further states that an increase in the number of
the proprietors of the soil is followed by diminished fertility, and
vice versa.
Prostitutes show as a rule a very low fertility. According to the data
of _Tarnowskaja_, the fertility of prostitutes in Russia is 34%, whilst
married women of similar ages in Russia exhibit a fertility of 51.8%.
_Gurrieri_ found 60% of prostitutes childless.
The fertility of female criminals was found by _Lombroso_ to be
undiminished. On the average, poisoners had given birth to 4.5 children,
other murderesses to 3.2 children, child-murderesses to 2 children; thus
the prisoners whose crime is commonly dependent on an abnormal eroticism
had a fertility above the average.
The diminished fertility of prostitutes depends in part upon frequent
venereal infection, in part upon the unfavourable influence of the
mercury and iodide of potassium administered for the cure of such
infection, also upon the frequency with which they consume excessive
quantities of alcohol, upon the excessive frequency of coitus, which
exercises a traumatic influence, upon the irregular mode of life, and
upon their disinclination to be burdened with children.
Conjugal fertility, that is to say, the ratio between legitimate births
and the number of married women between the ages of 15 and 50 years, has
declined in Germany during the last decades. It was:
During the years 1872 to 1875 29.7%
During the years 1879 to 1882 27.4%
During the years 1889 to 1892 26.5%
This decline is small, but it is much more manifest in urban than in
rural districts. This fact is shown by the following figures, relating
to fertility in Prussia:
1872 to 1879. 1894 to 1897.
In all towns 26.9 24.0
In Berlin 23.8 16.9
In other large towns 26.7 23.5
In rural districts 28.8 29.0
This difference depends principally on the fact that in the large towns
of Germany (and still more in those of France) the use of means for the
prevention of pregnancy is continually increasing, whereas the
population of the rural districts is as yet less familiar with the use
of these measures.
According to _Hellstenius_, conjugal fertility, that is, the number of
children per married couple, is as follows:
In the Netherlands 4.88
Norway 4.70
Prussia 4.60
Bavaria 4.55
Sweden 4.52
Saxony 4.35
England 4.33
Belgium 4.23
Denmark 4.18
France 3.46
_Talquist_, who has published a statistical investigation concerning the
modern tendency to diminished fertility, arrives at lower figures than
_Hellstenius_. According to him, conjugal fertility is:
In Prussia 4.11
England 4.10
Belgium 4.12
France 2.09
In various States of the American Union 2.5 to 3.0
From the Almanach de Gotha _Vacher_ obtained figures showing that each
family of the higher aristocracy has on the average the following number
of children.
In France 2.0
Italy 3.0
Germany 4.8
England 4.9
Russia 5.1
According to the figures we have published, the fertility of women
suffices for the production during the sexual life of a small number
only of children, averaging, in fact, 4 to 5 children per marriage. Many
mothers, however, give birth to a very large number of children. Among
73,000 families inhabiting Buda-Pesth, _Körösi_ found 300 mothers who
had had 15 children or more; 7 mothers who had each had 21 children; and
3 mothers who had given birth respectively to 22, 23 and 24 children.
A newspaper report states that the wife of a citizen of Buda-Pesth,
during the 43 years of her married life, gave birth to 32 children. In
the year 1902, a Bohemian woman gave birth to her twenty-fourth child.
_Stieda_ reports the cases of two mothers, one of whom had 21, and the
other 23 children. The wife of the German Emperor, Albrecht I, and the
wife of Prince Jost of Lippe-Biesterfeld, each bore 21 children.
The so-called _two-children-system_ obtains most commonly in France.
It is true that even in France there are on an average nearly three
children born per marriage; but if we take into account surviving
children only we find an average per family of 2.1 children only.
Similar conditions obtain in New England, and in Transylvania; and the
same practice is spreading throughout the United States. Another way in
which the attempt is made to keep down the population is that customary
in Alsace, where, if there are several children in a family one only
marries, in order to avoid a division of the family property. It cannot
be denied that in France, doubtless in consequence of the two-children
system, a somewhat widely diffused prosperity exists, a prosperity which
is lacking in the rare districts in France, such as Brittany, in which
limitation of the family is not practised. What a disastrous influence
the general use of measures for the prevention of pregnancy exercises on
the military power and political status of a nation has, however, in
recent years been made especially manifest in the case of France. In
that country, of ten million families, two million are absolutely
childless, and two million have only one child each, so that two-fifths
of the French families are as good as inactive in maintaining the
population of the country. The injury thus done to France is shown still
more clearly by a tabular comparison of the excess of births over deaths
in the German and French nations, respectively, during the two decades
1874 to 1894 (from _G. von Mayr’s_ _Population Statistics_).
Year. Germany. France.
1874 +13.4 +4.8
1875 13.0 2.9
1876 14.6 3.6
1877 13.6 3.9
1878 12.7 2.6
1879 13.3 2.5
1880 11.6 1.7
1881 11.5 2.9
1882 11.5 2.6
1883 11.7 2.6
1884 11.2 2.3
1885 11.3 1.4
1886 10.8 1.5
1887 12.7 1.3
1888 12.9 2.5
1889 12.7 1.2
1890 11.3 –0.3
1891 13.6 –0.5
1892 11.7 +0.1
1893 12.2 –1.2
1894 13.6 –0.4
To what an extent in all times, and among all peoples, the fertility of
women was esteemed, is shown by religious writings and traditional
customs which aimed at enabling a wife who had had no children by her
own husband, to seek other conjugal embraces. Among the Jews, it was the
duty of a man to marry his widowed and childless sister-in-law; if he
were unwilling or unable to perform this duty he was compelled to take a
part in a ritual termed “chaliza,” in which his foot was bared and the
bereaved woman spat upon him, because he was unwilling to maintain his
brother’s house. In the law book of the Hindoos of _Manus_, we read, “If
husband and wife have no children, it is proper for them to obtain the
desired offspring by a union between the wife and the husband’s brother,
or some other relative;” the child obtained in this way was legally
regarded as the child of the husband. _Confucius_ wrote: “If your wife
is barren, take a second wife; she must be subordinate to the first
wife, for her only duty is the bearing of children.” An analogy to this
ordinance is to be found in the Bible; Abraham’s barren wife Sarai says
to Abraham: “Behold now, the Lord has restrained me from bearing: I pray
thee, go in unto my maid; it may be that I may obtain children by her.
And Abraham hearkened unto the voice of Sarai.” In the same way the
barren Rachel speaks to her husband Jacob, “Behold my maid Billah, go in
unto her; and she shall bear upon my knees, that I may also have
children by her.”
_Luther_, in his treatise on marital love published in the year 1522,
bases, doubtless on the above biblical precedents, the following
statement regarding fertility: “If a sexually potent woman is married to
an impotent man, if she is unable to take any other man openly, yet is
unwilling to do anything dishonourable, she should say to her husband,
“Dear husband, you cannot fulfil your duty to me, and you have deceived
my young body, you have endangered my honour and my happiness, and in
the eye of God our marriage is null, forgive me therefore if I form a
secret union with your brother or with your nearest friend; the fruit of
this union will be yours in name, thus your possessions will not fall to
strangers, and you will willingly allow me to deceive you, because
involuntarily you have deceived me.””
In ethnography, the term _endogamy_ is used to denote a law or custom by
which marriage is allowed only within the limits of a specified race,
tribe, or caste; thus, in the Old Testament, Jews are forbidden to marry
women of other races. The ethnographical term _exogamy_ indicates the
prohibition of marriage between persons who are more closely allied, as,
for instance, the Mosaic prohibition of marriage within certain degrees
of blood-relationship. Such exogamic prohibitions persist even in the
legislation of the present day. In many ecclesiastical and national laws
we find the marriage of first cousins and of uncle or aunt with niece or
nephew forbidden; and even a prohibition of the marriage of a man with
his deceased wife’s sister.
_Hegar_ considers the danger of inbreeding to be very great in the human
species; for whereas in the lower animals breeders employ a methodical
and carefully considered selection of the best specimens, nothing of
this kind occurs among human beings; and the health of modern civilized
man is such that there are few families without a skeleton in the
closet. “Not only in families, but also in villages, in small and large
towns, even in classes, and in entire nations, certain peculiar
qualities, morbid tendencies, and predispositions, are handed down from
generation to generation. We have, for instance, the tendency of the
Jews to nervous disorders and diabetes, that of the English to gout,
that of the Germans to myopia.” _Strahan_ has therefore employed the
term “social consanguinity,” to indicate that by means of common
customs, environment, occupation, and mode of nutrition, a similarity in
type is produced, leading to a similar predisposition to disorders and
diseases transmissible from father to son.
The dangers of inbreeding are believed by _Hegar_ to be, under
present-day conditions, so considerable that he would allow the marriage
of near kin in exceptional cases only, and where the circumstances are
peculiarly favourable—for instance, where both parties to the projected
marriage are in excellent health, and where there is no great similarity
between them in feature or mental type. Certain anomalies transmitted
from remote ancestors, dependent on deeply-marked peculiarities of the
germ cells, may be so developed by inbreeding as to become absolutely
fixed characteristics. If the morbid manifestations can be traced back
for several generations, if the bodily defects and disturbances of
development (the so-called stigmata of degeneration), are well marked
and numerous, if the functional disorders of the nervous system and of
the sense organs are pronounced, leading to idiocy, insanity, epilepsy,
congenital deafmutism, blindness, instinctive criminality,—there is in
such cases little or no hope of the regeneration of the family. It dies
out, because the members are sterile; because they are confined in
prisons or asylums; or because the children, if any are born, are
deficient in vitality, and fail to reach maturity.
According to the brief summary of the subject given by _Hegar_, the
peculiarities of the offspring at the time of birth depend upon:
Factors which give rise to peculiarities of the germ-cells: