The hygienic problems of girls in industry will largely disappear when it becomes a matter of common knowledge that industrial efficiency is dependent upon physical efficiency. The physical efficiency of the worker cannot be maintained at its highest standard when the period allotted to rest is too short to allow the body to rebuild its tissues and dispose of the toxic products of fatigue. All activity must be balanced by rest. If this equilibrium between expenditure and income is disturbed, exhaustion ensues. If long continued, it results in permanent impairment of health. The organism poisoned by its own toxic products is incapable of productive effort and the output will steadily diminish as the fatigue increases. The present long working day causes a progressive diminution in the vitality of the worker, defeats its own end, and leaves the girl weak in the face of temptations. The housing of unmarried girls is a very serious question. Homes for working-girls require skillful management and a matron of insight and sympathy. The bedrooms may be small, but well lighted and ventilated. There should be a sunny dining-room, a library, several small parlors, attractively furnished, a gymnasium which could be used for dancing, shower baths, and an assembly room for concerts, lectures, and moving pictures. This should be in charge of a trained social leader who would direct entertainments and stimulate wholesome interests. With an establishment of this kind we should not find so many of our girls on the streets or seeking diversion in cheap theaters and dance halls. When girls are able to live,--not simply exist in the deadening monotony of alternation between work and sleep,--their heightened mental activity, interest, and enthusiasm will prove a valuable asset to employers. One of the chief requisites of the mental training of girls is a knowledge, supplied at the right time and in the right way, of the fundamental principles of reproduction. With such knowledge the girl's mind will not be distracted by curiosity, or become morbid, when, instead of intelligent response, the girl meets with evasions and attempted concealments. She should not receive this knowledge in the form of isolated facts, but as a correlated part of a great whole to be assimilated gradually. The girl who is trained in this way will understand and accept human reproduction as a natural process. Questionnaires show that a majority of girls hear the facts of reproduction at the age of seven or eight, a few younger, and a few at the age of ten,--almost none at a later age. The majority hear these facts from children a year or two older, a few from their mothers, and the rest from books. A large number experience a feeling of disgust which remains with them until they receive better information. Their questions disclose a depth of ignorance and misconception which is appalling.