For ninety years, the condition known as caisson sickness or disease has been studied by many observers. In 1912, Hill1 published the historic, physiologic, experimental and pathologic facts about caisson sickness. In 1896, Alt2 reported three severe cases of apoplectiform labyrinthitis in caisson workers. A workman, an hour after being subjected to a pressure of 2.2 atmospheres for more than two hours, experienced a sudden onset of severe pain in the ears, vertigo and absolute deafness. Another workman, within a few minutes after leaving the air lock, experienced the sudden onset of severe pains in the chest, serious collapse and total deafness. A third workman had cyanosis, dyspnea, deafness and marked vertigo. In all of Alt's cases, the Weber test was referred to the ear less affected. The return of hearing was slight, and the tympanic membranes were not ruptured. However, he quoted a case reported