a reaction seen in an animal deprived of its cerebellum; when the animal is placed on its back and the head strongly flexed, the four limbs become flexed in all their joints. Because of stimulation of receptors in the deep layers of the skin, light pressure made upon a toe-pad with the finger causes reflex contraction of the limb extensors; the limb is thus pressed gently against the finger, and when the finger is withdrawn slightly, the experimenter has the sensation that the finger is raising the limb or drawing it out as by a magnet.