ACTION OF LIGHT ON MUSCULAR FIBRES.
That light is capable of acting on muscular fibres, independently of the influence of the nerves, was mentioned by several of the old anatomists, but repudiated by later authorities. M. Brown Séquard has, however, proved to the Royal Society that some portions of muscular fibre—the iris of the eye, for example—are affected by light independently of any reflex action of the nerves, thereby confirming former experiences. The effect is produced by the illuminating rays only, the chemical and heat rays remaining neutral. And not least remarkable is the fact, that the iris of an eel showed itself susceptible of the excitement sixteen days after the eyes were removed from the creature’s head. So far as is yet known, this muscle is the only one on which light thus takes effect.—Phil. Trans. 1857.