Even in ancient times the existence of an open pathway between the ear and the respiratory tract was assumed. Up to the middle ages, however, Aristotle's idea that the air in the ear is an innate part of the body prevailed. The first anatomical description of the tube was given by Eustachius (1563). He still adhered to the concept of "innate air" and regarded the tube only as a pathway for draining pathological matter from the tympanic cavity. Duverney (1683) realized that an important function of the tube was replacing and adjusting the pressure of the air in the tympanic cavity. He thought that the tube is permanently open, thus offering a vent to the air, when the tympanic membrane is moving inwards and outwards. Valsalva (1704) discovered a muscle for opening the tube, and he presumed that in hearing this muscle would come into action. He described the maneuver that is named after him as a method to expel pus from the tympanic cavity into the external auditory canal. E.G. Guyot, a postmaster in Versailles, was the first to try catheterization of his own Eustachian tube via the mouth. Cleland (1741) inserted the catheter via the nose, and Wathen (1756) after studies on corpses described in detail the technique how to carry out this procedure. The therapeutic application of Eustachian catheterization as practiced by physicians such as Itard (1821) centered around irrigation with water and medications as well as inflation of various fumes. Deleau (1836) later advocated a douche of pure air and, in analogy to the auscultation of the lung, described the different noises that could be perceived during this procedure. Numerous models of pumps were constructed for this air douche, which became one of the most widely used therapeutical means in otology. There were also lethal incidents caused by cutaneous emphysemata. Toynbee realized that at rest the tube is closed and that there is a constant absorption of air in the tympanic cavity. The tube would be opened only by the act of swallowing and air would then be allowed to enter to equalize pressure. He believed that the maneuver he described, namely swallowing while the nostrils are closed, would produce a positive pressure in the tympanic cavity. He died when he applied these maneuvers in order to press fumes of chloroform or cyanic acid into his ears to treat his tinnitus. Politzer could demonstrate that after Toynbee's maneuver the middle ear is left with a negative pressure, and consequently, in 1861-63, he devised his own method for actively inflating the middle ear. The history of these events is described in detail and illustrated by a number of figures and anecdotal episodes.