The cerebral hemispheres can also readily be removed from birds. The pigeon so mutilated presents phenomena similar to those offered by the frog. He remains perfectly quiet, balancing himself readily on his perch, but with drooping eyes and sunken head, motionless so long as undisturbed. Move his perch, and he struggles to maintain equilibrium; fire a pistol near him, and he starts, only to fall back at once into his apathy; approach him in the dark with a bright light, and he gazes at the candle with a fixed stare, and sometimes follows its movements with his head; strike at him from the front, and he will draw back; pinch his toes, and he moves. It is therefore plain that he in a certain sense sees, hears and feels. Yet when perishing with hunger he never pecks at the corn which he sees placed before him, and if left alone dies. If, however, the food be placed in his mouth he swallows it eagerly, and by care can be kept alive for an indefinite period. Removal of the cerebrum has been repeatedly practised also upon the rabbit and the guinea-pig. The mutilated rabbit sits motionless whilst undisturbed, starves in the midst of plenty, cries out with its peculiar pathetic scream when pinched, draws back when ammonia is put to its nostrils; in a word sees, hears, feels in the same sense as does the pigeon, and, like the pigeon, undisturbed remains passive until death. Tread, however, upon the rabbit's foot, and perhaps with a little scream it darts forward in a furious race. Once started, it, like the brained fish, does not stop until exhausted or until it has dashed its head against some obstruction, for, unlike the mutilated fish, it does not have the power of avoiding obstacles.