An exhaustive review of the literature in all languages indexed at the New York medical libraries proved that congenital pneumothorax is an extremely rare condition, reports of only four previous cases having been found.Knowledge of pneumothorax in general dates back to 1803, when Itard named the condition and recognized its relation to tuberculosis.Laennec, in 1819, first described pneumothorax as a clinical entity, and was perhaps the first to diagnose the condition during life. He described the causes, symptoms and physical signs, and also gave the "succussion splash" its correct interpretation. The significance of this splashing sound had not heretofore been understood, as its presence was thought to indicate a moderate amount of pus in the chest, while its absence was interpreted as indicating a chest filled with pus. When pneumothorax was identified as a clinical entity, the meaning of the succussion splash became clear—a sign of the presence