The breath goes not merely as far as the man of material science knows. He knows only the vibrations of the air, going out and coming in, and he sees no further. Besides this there is pulsation: the beating of the heart and head, the pulse, all these keep a rhythm. Man very rarely thinks about what depends upon this rhythm. The whole life depends upon it! The breath which one breathes is certainly a secret in itself, it is not only a secret but the expression of all mystery, something upon which the psychology of life depends.