A further important consideration is the time at which the menarche occurs, and whether on the one hand it is at or near the average age, or whether on the other, as precocious menstruation, it is unusually early, anticipating the general bodily development, or again as retarded menstruation it is unduly delayed. In some cases of retarded menstruation, the external genital organs are thoroughly well developed, and it is menstruation only that remains in abeyance; but in other cases the external genitals are also backward in development, the pubes and mons Veneris being but sparsely supplied with hair, and the breasts remaining very small. In addition to these abnormal temporal relations of the menarche, certain other irregularities at the commencement of menstruation are worthy of note. Thus, the first menstruation may be normal, but thereafter amenorrhœa may persist for several months, or if the flow occurs it may be exceedingly scanty, or very pale in color; on the other hand, menstruation may be very profuse, lasting many days. The environment in which the young girl is placed during the period of her sexual development has a great influence on the processes of the sexual life and on the pathological disturbances that affect these processes. In working-class families the immoderate physical strain often thrown upon girls, in many cases continuous movements of the upper extremities whilst the lower extremities and the pelvis are absolutely quiescent, or conversely, an excessive employment of the muscles of the lower extremities—these circumstances in conjunction with insufficient nutriment, night-work, association when at work with persons of the opposite sex, and the frequent premature sexual stimulation, will combine to have a most deleterious effect. Amongst country-folk, indeed, the girl has the enjoyment of fresh air, and as a rule nutritive food, moreover, there are not so many occasions of nervous stimulation; puberty therefore arrives more slowly and gives rise to less disturbance; but the ignorance of the girls very frequently leads to an early experience of coition, the natural and unnatural consequences of which have then to be taken into account.