FOOD THAT IS ENTIRELY UNDIGESTIBLE.
There is no kind of food used which consists exclusively of indigestible matter. But it often is the case, that a certain amount of indigestible matter is mixed with nourishing food, and serves, by its mechanical aid, to promote the healthful action of the stomach and bowels. This is the reason why unbolted flour is deemed more healthful than fine flour, and is consequently preferred for dyspeptics. But where there is too great a quantity of such indigestible matter, or where it is not properly combined with digestible food, it proves injurious and often dangerous. This is the case when the skins and seeds of fruits are swallowed, which always pass off entirely undigested.