English: The Mechanics of Respiration. (from Hermann's Physiologie des Menschen),—where t is the trachea, l the lung, v the auricle of the heart, k the ventricle, i an intercostal space with its flexible membranous covering. When the interior of the vessel is rendered vacuous by exhaustion through the tube o, the walls of the lungs and heart are expanded until the limits of the containing vessel are accurately filled, while all flexible portions of the walls of the vessel (corresponding to the intercostal membranes and the diaphragm of the thorax) are sucked inwards.