Hearing is affected, besides all possible degrees of deafness, with the subjective sensations of ringing, whistling, or roaring sounds--tinnitus aurium. One form of this (as I conclude from observation in my own ears) depends upon spasmodic vibration of the tensor tympani or stapedius muscle. Sometimes the seat of the sensation is in the auditory nervous apparatus proper. It has, not seldom, a marked connection with brain-exhaustion. An attack of Menière's disease (labyrinthine vertigo) is often preceded by it. No constant signification, however, can be attached to aural tinnitus. Large doses of quinine or of salicylic acid will occasion it in many patients. Very briefly, deafness may be here disposed of by mentioning that, in greater or less degree, it may be produced by accumulated wax in the ear; obstruction of the Eustachian tube; thickness of the membrana tympani; perforation of that membrane; mucus or pus in the middle ear; disease of the ossicles of the ear; paralysis of the auditory nerve; typhus or typhoid fever; excessive doses of quinine or salicylic acid. Vertigo is chiefly of two kinds, dizziness or giddiness (swimming in the head), and reeling vertigo, or a disposition to fall or turn to one side or the other. Giddiness is produced by running or whirling many times in a circle, or, in some persons, by swinging rapidly or sailing. Reeling vertigo is mostly observed in connection with disorder of the brain or of the labyrinth of the ear (Menière's disease). Dizziness, with nausea, is common as a symptom of cholæmia (cholesteræmia of Flint) in what is popularly called a bilious attack. Delirium is present in many acute disorders, and not infrequently at a late stage in pulmonary phthisis. Its special study will be taken up in connection with the special articles upon these affections. Coma, or stupor, is met with chiefly in the following morbid states: severe typhus or typhoid fevers; malignant scarlet fever; small-pox; rarely in measles; pernicious malarial fever; uræmia; apoplexy; opiate narcotism, or that from chloral or alcoholic intoxication; asphyxia from inhaling carbonic acid gas, ether, chloroform, etc.; fracture of the skull with compression of the brain. For an account of aphasia and other morbid psychological manifestations the reader is referred to the articles on Aphasia, Insanity, Hysteria, etc. in this work. Physical and Instrumental Diagnosis will be treated in connection with those diseases in which they have special importance. {167} PROGNOSIS.