The transmission of an image to the brain through the sense of sight, is effected by the undulations of the ethereal medium, as exemplified in the action of light on the retina. The eye is a perfect camera obscura; the same arrangement of lenses, the identical mode of producing the picture. The choroid coat represents the ground glass on which the picture is focused, from which it is vibrated through the optic nerve to the brain, which is a mass of nervous molecules in their various combinations which produces THE THINKING POWER. THOUGHT is the motion of these particles of nervous matter charged with vitalized electricity.3