Sleep.--Amongst the most important of the factors that conduce to well-being both of body and mind must be reckoned an adequate amount of sleep. This has been made the subject of careful inquiry by Dr. Dukes of Rugby and Miss Alice Ravenhill. Both these trained and careful observers agree that the majority of young people get far too little rest and sleep. We have to remember that although fully-grown adults will take rest when they can get it in the daytime, young people are too active, and sometimes too restless, to give any repose to brain or muscle except during sleep. In the early years of adolescence ten hours sleep is none too much; even an adult in full work ought to have eight hours, and still more is necessary for the rapidly-growing, continually-developing, and never-resting adolescent. It is unfortunately a fact that even in the boarding schools of the well-to-do the provision of sleep is too limited, and for the children of the poor, whose homes are far from comfortable and who are accustomed to doing pretty nearly as their elders do, the night seldom begins before eleven or even twelve o'clock. It is one of the saddest sights of London to see small children dancing on the pavement in front of the public-houses up to a very late hour, while groups of loafing boys and hoydenish girls stand about at the street corners half the night. There is little wonder that the morning finds them heavy and unrefreshed, and that schoolwork suffers severely from want of the alert and vigorous attention that might be secured by a proper night's sleep. Great harm is done by allowing children to take work home with them from school; if possible, the day's work should finish with school hours, and the scanty leisure should be spent in healthy exercise or in sleep. Overcrowding.--In considering the question of adequate sleep it would be well to think of the conditions of healthy sleep. For sleep to be refreshing and health-giving, the sleeper ought to have a comfortable bed and an abundant supply of fresh air. Unfortunately the great majority of our people both in town and country do not enjoy these advantages. In both town and country there is a great deficiency of suitable dwellings at rents that can be paid with the usual rate of wages. In consequence families are crowded into one, two, or three rooms, and even in the case of people far above the status of day labourers and artisans it is the exception and not the rule for each individual to have a separate bed. The question of ventilation is certainly better understood than it was a few years ago, but still leaves much to be desired, and there is still an urgent necessity for preaching the gospel of the open window.