Self-observation, self-experimentation, and creative vision.
D000818:Animals; D003674:Defense Mechanisms; D005858:Germany; D049671:History, 18th Century; D049672:History, 19th Century; D006801:Humans; D006998:Hypochondriasis / Q000209:etiology; D010827:Physiology / Q000266:history; D010828:Physiology, Comparative / Q000266:history; D012106:Research / Q000266:history; D014785:Vision, Ocular