288 THE EAR Inflation of the Eustachian Tube. To complete the examination of the ear it is often necessary to try the effect of inflation of the middle ear cavity by driving air through the Eustachian tube into the tympanum. This proce- dure is important in diagnosis and prognosis, and as a method of treatment. It is of importance in diagnosis in that it gives information as to the patency of the tube, it demonstrates the presence of abnormal secretions within the tube or the middle ear cavity and it gives information as to the site of the Jife. 159. Syringeing the ear. lesion by its effect on the acuity of hearing. It is of value in prognosis as this depends largely upon the immediate improvement of hearing after inflation, and upon the length of time such improvement lasts. Inflation may be performed by Valsalva's method, by Politzer's method or by the Eustachian catheter. In Valsalva's method the patient pinches both nostrils and makes a forced expiration with his mouth shut. If the Eustachian tubes are patent air passes into the tympanum and the patient feels a crack or a sense of fullness in the ears. If the drumhead is inspected during inflation it is seen to move if there is nothing to interfere with its mobility. Valsalva's method is not always successful, even when the tubes are patent. Politzer^s method is carried out by means of a Politzer bag. This is a rubber bag about the size of a large orange, and is connected to an olivary nozzle which is inserted into the nostril. Both nostrils are then tightly closed by the finger and thumb of the surgeon's left,hand, the bag being held in his right. The patient is given a sip of water and is told to swallow, and the moment he does so the bag is forcibly squeezed. The most effective moment at which to compress the bag is that at which the larynx rises at the beginning of deglutition. Part of the air thus driven into the nose will pass into the middle ear on each side through the Eustachian tubes, unless they are very blocked. In the case of children the bag may be compressed during the act of crying.