These two objects are best accomplished by their thorough cleansing with a moderately stiff brush. Too soft a brush is insufficient for the purposes of removing the accumulations which collect upon the teeth. A tooth-powder or dentifrice of some kind will also be required. One of the simplest, and possibly also one of the very best, is composed of the following: Powdered borax 1/2 an ounce. Powdered orris root 1 ounce. Powdered white Castile soap 1/4 of an ounce. Precipitated chalk 3 ounces. Oil of cloves 2 drops. Oil of winter green 1/2 an ounce. This leaves nothing to be desired, and will be found satisfactory in every respect. It is customary to dip the tooth-brush into water, so as the better to enable it to take up the dentifrice. But it will be found an advantage if, after dipping the brush into water, it then be rubbed once or twice over a piece of white Castile soap. It will by this means pick up a larger amount of the powder. The teeth should be attended to after each meal, although cleansing them the last thing at night is an important duty, never on any account to be neglected. It must not be imagined, however, that even the foregoing is sufficient. Particles of food, which the brush fails to remove, collect between the teeth, and, if allowed to remain, ultimately lead on to decay. This is most likely to occur when the teeth are crowded close together in the jaw. But under all circumstances, whether the teeth be closely set together, or whether they be more widely apart, a piece of floss silk should be passed between them daily, so as to remove any adherent particles, and at the same time to thoroughly cleanse the sides of the teeth. CHAPTER IV. BEDROOM VENTILATION