The nervous system is divided into sensory (diacritic) and emotive (coenesthetic) organizations, a duality which is useful in elaborating the 'functional approach'. Spitz largely uses Wallon's details in describing the properties and function of the two systems. The concept seems to clarify clinical details in the cases cited by Ribble of disturbed function in infants where the sensory system has failed in its function; the organism falls back on its primitive emotive organization which is insufficient for adequate response and reacts only with the cataclysmic manifestations well-known in psychiatry. Yet it is the emotive system which is amenable to treatment either violently as in the shock therapies, or gradually as in psychoanalysis. The advances in ego analysis point the way to use of the sensory system in influencing the emotive system.