Note 53 — Chapter II · HABITS WHEN WILD.

“When an animal moves progressively an hypothenuse is produced, which is equal in power to the magnitude that is quiescent, and to that which is intermediate. But since the members are equal, it is necessary that the member which is quiescent should be inflected either in the knee or in the incurvation, if the animal that walks is without knees. It is possible, however, for the leg to be moved, when not inflected, in the same manner as infants creep; and there is an ancient report of this kind about elephants, which is not true, for such animals as these, are moved in consequence of an inflection taking place either in their shoulders or hips.” (Aristotle, De Ingressu Anim. ch. ix. Taylor’s Transl.)