In a normal condition, and when awake, respiration takes place without noise when the movement is moderate; but when inspiration and expiration are strong and deep, it is accompanied by a noise caused by the air passing through the nasal passages or the mouth. During sleep the column of air breaks against the soft palate and produces snoring. Besides these sounds, which are exterior to the chest, there are others produced by the passage of the air through the bronchial tubes; and when the ear is applied to the chest of a person in good health, a soft and regular murmur is heard in rhythm with the respiration; this is called the vesicular murmur. Several morbid causes change the nature of this murmur, suppress it, or produce others. These are so many signs which enable the physician to determine the condition of the respiratory organs.