COUGHING (AS. cohbetan, Dutch kugchen, to cough, 51HG. kachr». kichor, (ter. lowehrn, keielien, to gasp: imitative of the sound). Con sidered physiologically, coughing consists, first, in a long inspiration which fills the lungs to a greater extent than usual : second, in a closure of the glottis. or narrow opening in the organ of voice (see LARYNX). at the commencement of the act of expiration: and third. in a sudden forcing open of the glottis by the violence of the expira tory movement. In this way. a blast. of air is driven upward from the lungs through the mouth, which carries with it anything that may he present and cause irritation in the air-pas sages. Coughing may occur from irritation in the back of the throat, in the larynx, trachea, or bronchial tubes, and may lie excited by irritant or by articles of food or drink—such as even a drop of water or a crumb of bread—mak ing their way into the air-passages instead of into the (esophagus, or hr excessive or morbid secretion from the walls of the air-tubes, ox even by the entrance of cold air, when the lining membrane of the air-pasAnges is abnormally ir ritable. Cough is reflex and involuntary gener
ally, and is due to irritation of the terminal fibres of the pneumogastric nerves, which are distributed to the mucous membrane of the res piratory tract. The object of coughing in the animal organism is unquestionably to guard against the danger of the entrance of mechanical and chemical irritants into the air-passages; and accordingly the mucous membrane, especially of their upper part, is endowed with a most ex quisite sensibility, which, when aroused by me chanical irritation or by disease, provokes inces sant coughing until the cause of the irritation is removed. Cough is a common symptom of all diseases of the organs of respiration, as well as of inflammatory affections of the throat. tonsils, and nose. The treatment of cough depends upon the cause. See PNEUMONIA: BRONCHITIS; PLEU RISY: TUBERCULOSIS.