Page:Popular Science Monthly Volume 1.djvu/427

Rh it made no attempt at self-defence, neither resisting nor escaping. In fine, it lost every trace of intelligence, for it neither willed, remembered, felt, nor judged: yet it swallowed food when the food was put into its mouth, and fattened. In these cases, as in that of the injured man, the involuntary systems sustained the animal life. It is the same in sleep.



When we look at these phenomena, as anatomists, we find a reason for them in structure and character of parts. The involuntary muscles have a special anatomical structure; and the nervous organism that keeps the involuntary muscles in action is a distinct organism. There are, briefly, two nervous systems: one locked up in the bony cavity of the skull and in the bony canal of the spine, with nerves issuing therefrom to the muscles; and another lying within the cavities of the body, with nerves issuing from it to supply all the