Removal of the cause of, or allaying, the irritability of the air-passages is to be desired, and the treatment for respiratory troubles is more generally dealt with under the heading of pulmonary diseases. It is, however, found that acid tonics in combination with such soothing agents as bella-donna, hyoscyamus, camphor, and opium have the effect of reducing the volume of, or drying up, the phlegm which is a troublesome symptom of chronic bronchitis.