In view of the great importance of so-called general sensation, or common sensation, in clinical work, particularly in the diagnosis of nervous and visceral diseases, it is rather surprising that we have so often been content with a very uncritical analysis of this sensation complex.
Nearly twenty-five years ago Gaskell from the physiologic side and His from the embryologic side established the now classical four-root theory of the composition of the spinal nerves, recognizing in each pair somatic and visceral motor and somatic and visceral sensory components. More recently Sherrington1 has elaborated a very fruitful physiologic analysis, dividing the sense organs (receptors) of the body into: (1) interoceptors, or visceral sense organs of the digestive tract and its derivatives; (2) exteroceptors, or somatic sense organs of the outer body surfaces for impressions coming from the outside world, and (3) proprioceptors, sense organs of the muscles, joints, tendons, etc., adapted