American National Red Cross, American Red Cross Text-Book on Home Hygiene and Care of the Sick
“ Of all symptoms pain is the one which interests patients the most. We here emphasize the truth, too little understood, that pain is an unpleasant sensation, nothing more, and is never imagined. Imagination may be its cause, but the pain thus produced hurts just as truly as pain produced by a real disease. Pain is only a phenomenon of consciousness; it is always real, even that felt in a dream. If the patient is too unconscious to feel it, there simply is no pain, no matter how badly the person's body is injured. ”
