Old persons require, as a rule, less sleep than those of middle age, just as they require less food, because their nutritive processes are less active than when they were younger, and perhaps because their mental efforts also are less forced and attended by less exertion and more deliberation. Women, generally speaking, require more sleep than men, at least under like circumstances, apparently because in their case the same efforts involve greater fatigue. VENTILATION OF BEDROOMS Rooms which are to be slept in after having been occupied during a whole evening must be thoroughly ventilated before the occupant prepares for bed. Doors and windows must be thrown open for several minutes, the gas or lamp put out, and the air completely changed, no matter how cold it may be outside. This is the only way to obtain refreshing sleep. On going to bed the usual ventilating arrangements should then be followed, but the great point is to change the air thoroughly first. REGULARITY OF HABITS The importance of regularity and punctuality in every circumstance of daily life is not sufficiently realized. The more often and regularly any act is performed the more automatic it tends to become, and the less effort, whether mental or physical, attends its performance. This is a matter of daily experience and observation, and is true not only of mental work and manual or mechanical exercises, but of the organic functions of the body. Quite apart from the harm done by too frequent eating or too prolonged periods between meals or want of rest, the brain finds itself ready for sleep, the stomach for digestion and the bowels for action at the same hour every day, when these acts are performed with unbroken punctuality, and the strain upon the system to adjust itself to new conditions is therefore reduced to a minimum. _GENERAL HEALTH CONDITIONS_ _Guard Your Water Supply—How Diseases Are Classified—How to Prevent Contagion—Care of the Sick Room—Disinfection, Its Importance and Its Methods—Period of Isolation or Quarantine—Duty of All Households Where Sickness Has Invaded, to Guard Others Against Its Spread._ Man cannot preserve his health entirely by his own caution as to his food and personal habits. His surroundings enter into the matter at all times. By this is meant the house in which he lives, its situation and conditions, as well as the community itself. Fortunately, in this country we have not yet become so overcrowded as to forbid ordinary care in the matters of drainage, light, ventilation and other requisites. Americans should congratulate themselves that their ample country and general prosperity enable them to regulate their food, their habits and the conditions around them in high degree. At the same time the fact that these things are so generally within our control places upon us the obligation to do what we can for the community to maintain the general health.