The injunction “Know thyself” was inscribed in letters of gold over the portico of the temple of Delphi. We can know ourselves only by thoughtful observation and reflection. General forms of exercise may be presented, but we must consider whether our present health and physical condition will not require some modification of the prescribed forms. Certain modes of bathing and specific rules for diet and sleep may be good for the multitude and yet unsuited to particular individuals. Any marked cha ...