Among all human races the signs of maturity appear later and less distinctly in the male than in the female. In Europeans the period of puberty coincides with the second period of increased bodily growth, which ceases in the male between the sixteenth and the eighteenth year, and in the female between the fourteenth and the sixteenth year. The end of the puberty period may, however, in individual cases, be postponed for some years. The exact time of the advent of sex maturity, which, on account of their menstruation, can be fixed much more readily in girls than in boys, varies not only individually, but racially. The same applies to the difference in time between the advent of maturity and the cessation of bodily growth. Sexual maturity, as well as the cessation of bodily growth, takes place much earlier in Europeans than in some of the primitive peoples. Among other primitive peoples, however, maturity occurs comparatively late, and bodily growth ceases shortly after. To the latter belong certainly some of the peoples living in the tropics.

The opinion still prevails that climate has a considerable influence on the advent of maturity. Rudolf Martin (1915) remarks: "Races living in the tropics grow more quickly and mature earlier than the races living in temperate zones. This is undoubtedly due to the earlier advent of puberty."

As regards the Japanese, E. Baelz had already in 1891 disputed the statement that they mature early. He found, however, that the growth of both sexes ceases in Japan earlier than in Europe; still sex maturity in the female does not occur earlier. According to the concordant statements of female teachers of various girls' schools, the Japanese girls, in fact, reach maturity later than European girls, and half-caste girls take a medium position.

Since then reliable data about the advent of maturity among non-European races have seldom been given, but those to hand show that most probably even among coloured primitive people puberty generally occurs late.

Very important material has been collected by O. Reche in Matupi (New Pomerania, Melanesia), with the assistance of the Catholic mission of the place. He found that the rhythm of growth of the Melanesians corresponds on the whole to that of the Europeans, except that the growth ceases altogether a few years earlier. Development in height is finished on the whole in girls at the beginning of the seventeenth year, and in boys in the eighteenth year. But, as regards the advent of puberty, Reche's researches led to the surprising result that all Matupi girls, with the exception of those seventeen years old, had not yet menstruated. Reche remarks that this strikingly late appearance of menstruation is also known to the missionaries, because in order to prevent early marriages they only consent to the marriage of a girl after the first menstruation has taken place. Reche's experience is in strong contradiction to the belief formerly taken for granted, for puberty occurs among these inhabitants of the tropics not only not earlier, but, on the contrary, later than with the Europeans living in temperate climates. Of importance is the fact that in the Matupi natives puberty coincides with the highest point of the curve of growth, namely, with the end of the development in height. Puberty commences when growth ceases. It almost seems as if the advent of maturity absorbs all the strength and hinders further growth. It is quite different with Europeans in this respect: the beginning of puberty falls with them in the second period of growth (in boys the twelfth to the sixteenth, in girls the eleventh to the fourteenth year), and therefore long before growth ceases altogether.

It would seem that the conditions existing among Europeans are the primitive state, as with the majority of animals also puberty begins before the cessation of growth.

Reche reports further that, corresponding to the late puberty, the secondary sexual characteristics also appear exceptionally late in Matupi children. This is the chief reason why the boys and girls, especially as they are small, appear remarkably young even shortly before maturity, and why their age seems much less than it actually is. The first beginning of the change from the areola mamma to the budding breast shows itself among the Matupi girls not before the sixteenth year; the development of the breast seems to coincide with the first menstruation. Axillary hair did not appear in sixteen-year-old Matupi girls, with one exception; and it was scanty in those seventeen years old, though it is generally copious in adults. There was also no trace of a beard in seventeen-year-old boys, though it is well developed in the older men. It must be added that the late differentiation of secondary sexual characteristics is also noticeable among other coloured races, as, e.g., among the Philippines and other Indonesian races.

Among the Papuans of New Guinea also sex maturity occurs late. As Richard Neuhaus wrote, according to information given by missionaries who have lived for a long time among the natives on Tami and among the Jabim, the first menstruation generally appears in the fifteenth to sixteenth year. Young males look very undeveloped up to the sixteenth year. Neuhaus thought this late maturity was the result of bad feeding, though it does not appear from his other descriptions that the economic conditions of the Papuans are especially unfavourable.

A. E. Jenks reports of the Igorots on Luzon that boys as well as girls attain puberty at a late age, generally between fourteen and sixteen years. The civilised Ilkano people settled among the Igorots definitely declare that the girls do not menstruate before they have reached the sixteenth or seventeenth year. A considerable error as regards their age seems to be excluded with these people, who have lived a long time under European influence.

Of the Andamanese, a pigmy race, Portman and Molesworth write that puberty appears in boys and girls round about the fifteenth year. Bodily growth is finished at eighteen years, and is in any case after maturity very trivial.

Eugen Fischer makes the following statements about the Bastards in German South-west Africa: "In one family five out of six daughters menstruated for the first time at the age of fifteen, one at the age of sixteen. One Bastard woman had first menstruated at the age of seventeen, three of her daughters at thirteen, the fourth, who was anÆmic, at seventeen. Another Bastard woman, who herself had her first menstruation at fifteen, had two daughters from a white man who had reached puberty at sixteen and seventeen years of age. A girl with distinct anÆmia stated that she had had her first period at sixteen years, her sister even as late as eighteen," Fischer knows of three girls that became mature at sixteen, fourteen, and thirteen years. L. Schultze reports that with the Hottentots the first menstruation appears, as a rule, between the ages of thirteen and fifteen.

There is, unfortunately, no information to be had about the negroes with regard to this subject. The puberty rites practised by them give no clue to the real age at the advent of puberty.

AleŠ Hrdlicka (pp. 125-129) tried to determine the age of puberty among Indian girls of the south-west of the United States by their height, as definite statements of age are not to be had. This method is not without objection, for it is certain that individuals who have attained puberty are decidedly taller than persons of the same age who have not reached maturity. Hrdlicka found that of those examined in the twelfth or thirteenth year one-third of the Apache girls and as many as three-quarters of the Pima girls had already menstruated. In the age class of thirteen to fourteen years four-fifths of the Apache and nine-tenths of the Pima girls had already menstruated, while of forty-six older girls only one had not yet attained puberty. The first signs of breast development were noticed by Hrdlicka in clothed Indian maidens whose ages he estimated to be from eleven to twelve years. But it was only between fifteen and seventeen that the girls acquired the typical womanly form; until then they have, as Hrdlicka says, "a somewhat male appearance." In youths the beard begins to grow at the fifteenth or sixteenth year. The climate is moderate in the country of the Apache and Pima Indians; the days are decidedly hot in the low-lying regions, but the nights are generally cold in these regions, even in summer.

In comparison it may be noted that, according to H. P. Bowditch's investigations in Boston, nearly four-fifths of the white girls born in America mature between the thirteenth and seventeenth year. Puberty is reached relatively most often between the ages of fourteen and fifteen, though over 40 per cent. of 575 girls examined had not yet menstruated at the completed fifteenth year.

Within one and the same race the conditions of life seem to have a great influence on the age of puberty and bodily development. Unfavourable conditions produce a retardation of puberty; favourable conditions accelerate it. This may be the chief cause why the beginning of puberty varies individually by several years.

There exists so far no definite explanation of the racial differences in the age of puberty. Reche says, "It is conceivable that the characteristically late maturity of a tropical race (like that of the Melanesians) may gradually have been acquired by the unfavourable influence of too hot a climate or of continual underfeeding acting on many generations."

It is remarkable that, in contradistinction to the Melanesians, the Indians become mature very early, and the same applies most likely to the Australians. In India, as in Australia, sexual intercourse is begun at a very youthful age, among the girls often long before the first menstruation. It is possible that on account of this the age of puberty is lowered, so that girls who mature late are more easily injured and perish in greater number than the girls maturing earlier, who are less injured by the premature sexual intercourse. The male sex may have been influenced in the same direction through heredity.

Just as physical maturity, so is the cessation of generative power and bodily decline more marked in women than in men. In Middle and Northern Europe, procreation generally ceases with women of an age between forty-five and fifty years. Numerous birth statistics from all countries of this continent show that birth in women over fifty years old is very rare. It is not quite clear how the case stands in this respect among the coloured races. Hrdlicka reports of the North American Indian women that with them the climacterium occurs apparently at about the same age as with European women. It must be taken into consideration that accurate statements of age are wanting, and that the age of Indian women can easily be greatly overrated. Otherwise it has generally been reported of coloured women that they age rapidly, and that their reproductive period is comparatively short. In North-west Brazil the Indian girls marry as soon as in their tenth to twelfth year, on account of their rapid development. Early maturity and marriage may be one of the chief causes of their rapid decline. The Indian women are generally beyond their prime at the age of twenty. Their straight figure is frequently covered with a disgusting accumulation of fat, and the elasticity of movement gives way to indolence. Other women become very thin after several confinements, their features become sharp and bony, and among old women one often comes across real hag-like creatures with half-blind, running eyes (Koch-GrÜnberg, II., p. 149).

In India the women of the Dravidian as well as of the Mongolian races age rapidly. Their generative power rarely lasts longer than the beginning of the forties. Among the pigmies the time of procreation is said to be equally short (Portman and Molesworth). Spencer and Gillen say that with the Australian women a rapid bodily decline takes place as early as the twenty-fifth and at the latest in the thirtieth year, which cannot be attributed to exceptional privations or harsh treatment. The Australian women apparently reach the age of fifty years or more only exceptionally.

Jochelson (pp. 413 et seq.) writes that the Koryak women age very rapidly. They cease to bear children at about the age of forty. Other travellers have made statements about the great age that the Koryaks are said to attain. Jochelson's thorough-going investigations showed that of 284 persons only thirteen could possibly have been over sixty-five years old, and among them there was only one really old man.

Schultze (p. 297) mentions two Hottentot women who had given birth at the age of forty-seven, and another who still had her period at fifty-five. Among the negresses late births also occur. Unfortunately, ethnographical literature only rarely gives facts with regard to this subject.