1754

Leopold Auenbrugger, working at Vienna’s Spanish Military Hospital, discovers significance of thoracic percussion in diagnosing pleural effusions (esp. in TB). He compared the physical signs with post-mortem findings, in which he also injected fluid into pleural cavity and showed it was possible by percussion to tell exactly the limits of fluid present. His findings, largely ignored in his own lifetime, were published seven years later in Inventum novum ex percussione thoracis humani ut signo abstrusos interni pectoris morbos detegendi (a book of 95 pages), where he initially described the sonic qualities of the thorax in terms of drums and their variable timbral possibilities (17). He used precise musical terminology to describe various thoracic sounds. After noting that ‘the healthy human thorax sounds, if it is struck,’ he added that ‘the sound the thorax gives is observed to be such as in drums [tympanis] when they are covered by a cloth or by another fabric made of thick wool’. His description “showed close knowledge of contemporary drum technique, including the use of muting cloths called coperti, used to muffle the sound of the timpani” (18). “Going far beyond pulse observations or scrutiny of such manifest signs as stool, urine, or the visual appearance of the skin, percussion treated the body as a musical instrument capable of producing deeply revealing sounds, for the first time allowing the prediction of disease in the absence of any other symptoms” (20).