Marsh says: "Every human movement, every organic act, every volition, passion, or emotion, every intellectual process, is accompanied with atomic disturbance." Picton says: "The soul never does one single action by itself apart from some excitement of bodily tissue." Emerson says: "The rolling rock leaves its scratches on the mountain; the river its channel in the soil; the animal its bones in the stratum; the fern and leaf their modest epitaph in the coal. The falling drop makes its sculpture in the sand or stone.... The ground is all memoranda and signatures, and every object covered over with hints which speak to the intelligent. In nature this self-registration is incessant." Morell says: "The mind depends for the manifestation of all its activities upon a material organism." Bain says: "The organ of the mind is not the brain by itself; it is the brain, nerve, muscles, organs of sense, viscera.... It is uncertain how far even thought, reminiscence, or the emotions of the past and absent could be sustained without the more distant communication between the brain and the rest of the body." And, thus, as we consider the subject carefully we see that psychology is as much concerned with the physical manifestations of the mental impulses and states as with the metaphysical aspect of those states--as much with the Outer Form as with the Inner State--for it is practically impossible to permanently separate them. As an illustration of the physical accompaniment or Outer Form, of the psychical feeling or Inner State, the following quotation from Darwin's "Origin of the Emotions," will well serve the purpose: