once, like Sancho Panza, but alternately, so that all can have a fair share of labor. The tooth is like the arm; use it regularly, and it will be healthy, well-developed, handsome; give it little or nothing to do, and it becomes weak, soft, unsightly.
This is all the advantage (for the teeth) there is in "whole-meal bread," bran bread, and so forth, which of late years have been much preached about. There is no necessity for such unusual diet. In the army it was remarked how well the men's teeth were preserved. A dentist of acknowledged skill has told us he saw this in many instances, and attributes it to the "hard tack," the dry, tough soldier-crackers the men ate. They were forced to chew them thoroughly, and thus their teeth had more to do, and were the better for it.
There is no need of "hard tack," either. Simply masticate deliberately and well such food as is set before you, and the result will be the same.
But looking at this sentence again, we are constrained to modify it. Food may be, doubtless daily is, set before you which, so far as your teeth are concerned, you will do wisely to decline, or to partake of but sparingly. Any food or drink very hot or cold injures the enamel. This "enamel" is the external, white, glittering part of the tooth. It is chiefly lime, and anything sour corrodes or softens the lime, to the injury and final destruction of the whole tooth. There-
