Universally through the human species women arrive at puberty sooner than men. But that age is different in different countries, and seems to depend on the temperature of the climate and the quality of the food. Among people who live at their ease, and feed plentifully, children arrive at this state two or three years sooner than those in the country, and among the poorer classes of people, whose food is less nourishing and more scanty. In the southern parts of Europe, and in cities, the majority of girls attain puberty at about twelve years, and boys at fourteen; but in the regions of the north, and in country places, the former are hardly so at fourteen, or the latter at sixteen.
Should it be asked why females in every climate are capable of engendering more early than men? It might be satisfactorily replied, that men are much larger and stronger, their bones more hard, their muscles more firm and compact, and therefore a longer time is required for their growth. And as it is not till after the growth is completed that the superfluity of the organic particles is dispersed into the parts of generation, females must of course arrive at maturity sooner than the males.
In the hot climates of Asia, Africa, and America, girls are generally mature at ten years of age, and often at nine; and though the menstrual discharge is less copious in warm countries it is yet more early. The intervals between are nearly the same in every country, and in this respect there seems to be a greater difference between individuals than between nations. In the same climate and nation some women are subject to the menstrua at the end of every fifteenth day, while others are free from them for six weeks; but a month, however, two or three days over or under, is the usual period.
The quantity of the discharge seems to depend on the quantity of nourishment, and of insensible perspiration. Women who eat much, and exercise little, have the most copious discharge? in warm countries it is always least, because the perspiration is great. As to its duration, it is generally from three to four or five days, though sometimes to six, seven, and even eight days.
The _material_ causes of it are supposed to be a superfluity of blood and nutritive particles. The symptoms which precede are certain indications of repletion; as heat, tension, swelling, and the pains which women feel, not only in the parts themselves, and the adjoining ones, but also in the breasts, which swell and discover a surplus of blood by the _areolæ_, or the circle about the nipple, becoming of a deeper colour. The eyes are oppressed, and underneath their orbits the skin assumes a blue or violet tint; the cheeks are flushed; the head is heavy and full of pain; and the whole body in general is in a state of oppression from the surcharge of blood.