Not all living flesh is painful; nor is all nerve, not even all sensory nerve. There’s no taint of pain, real pain, in the sensations of the optic nerve. If you wound the optic nerve, you merely see flashes of light,—just as disease of the auditory nerve merely means a humming in our ears. Plants do not feel pain, nor the lower animals; it’s possible that such animals as the starfish and crayfish do not feel pain at all.
