Note 21 — THE GAME UP WITH REPEAL AGITATION.

Footnote 21: (return) We say living, because every attempt hitherto made to explain sensation, has been founded on certain appearances manifested in the dead subject. By inspecting a dead carcass we shall never discover the principle of vision. Yet, though there is no seeing in a dead eye, or in a camera obscura, optics deal exclusively with such inanimate materials; and hence the student who studies them will do well to remember, that optics are the science of vision, with the fact of vision left entirely out of the consideration.