6. While the use of tobacco is less pernicious than alcohol in its effects, et it exerts a profound disturbing influence upon the nervous system, and gives rise to various functional and organic diseases. This is the verdict of those who have given the subject the most study, and who have had the best opportunities for extensive observation. Suddenly fatal results have followed excesses in the use of tobacco. Therefore, the habit should be avoided, or if already acquired, it should be immediately abandoned. 7. The clothing should be light and porous, adapted in warmth to the season. It is especially important that persons in advanced life should be well protected against vicissitudes of heat and cold. Exposure is the cause of almost all those inflammatory diseases which occur during winter, and take off the feeble and the aged. The under-garments should be kept scrupulously clean by frequent changes. Corsets or bands which impede the flow of blood, compress the organs of the chest or abdomen, or restrict the movements of the body, are very injurious, and should not be worn. Articles of dress which are colored with irritating dye-stuffs, should be carefully avoided. 8. It matters not how varied a person's vocation may be, change, recreation, and rest are required. It is an error to suppose that more work can be done by omitting these. No single occupation which requires special mental or physical work, should be followed for more than eight hours out of the twenty-four. The physical organism is not constructed to run its full cycle of years and labor under a heavier burden than this. Physical and mental exercise is conducive to health and longevity, if not carried too far. It is erroneous to suppose that excessive physical exertion promotes health. Man was never intended to be a running or a jumping machine. In mental work, variety should be introduced. New work calls into play fresh portions of the brain, and secures repose for those parts which have become exhausted. Idleness should be avoided by all. Men should never retire from business as long as they enjoy a fair degree of health. Idleness and inactivity are opposed to nature. 9. The average length of time which a person ought to sleep is eight hours out of the twenty-four, and, as a rule, those who take this amount enjoy the best health. The most favorable time for sleep is between the hours of 10 P.M. and 6 A.M. All excitement, the use of stimulants, and excessive fatigue tend to prevent sleep. Sleeping rooms should be well ventilated, and the air maintained at a equable temperature of as near 60° Fahr. as possible. An inability to sleep at the proper time, or a regular inclination to sleep at other than the natural hours for it, is a certain indication of errors of habit, or of nervous derangement.