In this paper Flescher discusses a number of conditions in the sensory area, especially pain and the absence of pain, and how they relate to the body scheme. Phenomena such as phantom limb and anosognosia have interested neurologists as well as psychiatrists for many years. Flescher makes an important contribution to this rather controversial field. He assumes a common biologically determined denominator to explain painfulness, anesthesia, and mutilations of the body scheme—the instinct of self-preservation, derived from both basic instincts, the erotic and the aggressive. Confronted with instinctual danger, the ego sacrifices parts of itself by withdrawing cathexes. The dynamic source for this self-defense is the aggressive instinct. He correlates fear (anxiety) in the psychic field with pain in the somatic field. Pain is an expression of an (unconsciously