Franklin Chase Clarke, Popular Science Monthly (1876)
“ They result simply from fear, as any one may easily prove for himself: the animal appreciates the power acting on it, and the uselessness of resisting the injury or the supposed injury inflicted. Here, of course, we must allow animals a certain amount of intelligence for such perceptions. After the animal has made resistance, and finds itself incapable of removing the obstacle, it lapses into quietude, to act again only when it supposes the restraint has been removed. ”
