A small, shallow, yellow ulcer, appearing on the inside of the lips or beneath the tongue during some disorder of the digestion. It is very tender when touched and renders chewing or talking somewhat painful. Treatment consists of touching the ulcer carefully with the point of a wooden toothpick which has been dipped in pure carbolic acid (a poison) and then rinsing the resulting white spot and the whole mouth very carefully, so as not to swallow any of the acid.

Inflammation of the mouth occurs in two other general diseases, in syphilis and rarely in diphtheria. In children born of syphilitic parents, deep cracks often appear at either side of the mouth and do not heal as readily as ordinary sores, but continue a long time, and eventually leave deep scars. In diphtheria the membrane which covers the tonsils sometimes spreads to the cheeks, tongue, and lips, but in either case the general symptoms will serve to distinguish the diseases, and neither can be treated by the layman.