Henley's Twentieth Century Formulas…
“ Tooth Powders And Pastes.—Although the direct object of these is to keep the teeth clean and white, they also prevent decay, if it is only by force of mere cleanliness, and in this way (and also by removing decomposing particles of food) tend to keep the breath sweet and wholesome. The necessary properties of a tooth powder are cleansing power unaccompanied by any abrading or chemical action on the teeth themselves, a certain amount of antiseptic power to enable it to deal with particles of stale food, and a complete absence of any disagreeable taste or smell. ”
