III.

Life is an action; the principle of life, whatever may be its nature, is eminently and visibly a principle of excitation, of impulsion, a motive power.

"It is taking a false idea of life," says Cuvier, "to consider it as a simple link which binds the elements of the living body together, since, on the contrary, it is a power which moves and sustains them unceasingly."

These elements do not for an instant preserve the same relation and connection; or, in other words, the living body does not for an instant keep the same state and composition. "This law," adds Flourens, "does not affect alone the muscles, viscera, and tissues, but there is a continual mutation of all the parts composing the bone." These views have been substantiated by the extended experiments of Chossat, of Von Bibra, and a host of experimentalists, showing how positive and decided are the changes in the material composition of the body, and especially the constitution of even the bone from the influence of food.