BREATH

the aur which i ues from the lungs during respiration through the nose and mouth. operation is performed without effort, but still causes a motion in the external air, before the and mouth. The air expired is the vehicle of sound and speech. A smaller portion of oxygen and a larger portion of carbonic add is contained in the air which is exhaled than in that which is inhaled. There also aqueous particles in the breath, which are cipitated by ihe coldne of the external aur, in form of visible vapour; likewise other substances which owe their origin to secretions in the month, nose, windpipe, and lungs. These cause the changes in the breath, which may be known by the smell, the other qualities of the air. In youth, the breath is insipid, and contains add; it loses these qualities after the age of puberty, and becomes more agreeable. With advancing age, it becomes again unpleasant. A bad breath is often caused by local affections the nose, the mouth, or the windpipe; viz. by ulcers in the nose, caneerous polypi^ by discharges the mouth, by sores on the lungs, or peculiar secretions in them. It is also caused by rotten teeth, imporitiee in the mouth, and by many kinds of (viz. horse-radish, onions, and also by flesh, if used the exclusion of other food), and by fevers. In last case it often varies with the character of the ease. The remedy for this complaint must depend on the causes which produce it. Substances of aromatic kind, which have a strong rich smell, should \ye chewed to diminish its offensivene . But often impo ible to remove this unpleasant disorder. BREATHING. See RESFiBATioy.