ETIOLOGICALLY, tinnitus aurium has remained unexplained. Though a number of theories have been advanced in the attempt to identify and explain the factors responsible for this distressing symptom complex, none of the theories has ever been proved either histologically or therapeutically. During the last twelve years I have been conducting an extensive research study of the symptom complex known as tinnitus aurium in its relation to disease of the middle and the inner ear. In lesions of the middle and the inner ear of nonsuppurative origin the following observations were made: