"Illness or disease is only Nature’s warning that filth has accumulated in some portion or other of the body; and it would surely be the part of wisdom to allow Nature to remove the filth, instead of covering it up by the help of medicines. Those who take medicines are really rendering the task of Nature doubly difficult. It is, on the other hand, quite easy for us to help Nature in her task by remembering certain elementary principles, by fasting, for instance, so that the filth may not accumulate all the more, and by vigorous exercise in the open air, so that some of the filth may escape in the form of perspiration. And the one thing that is supremely necessary is to keep our minds strictly under control. (Introduction)"