By watching an infant taking the breast or bottle, some information can be obtained of the condition of the mouth and throat, and of the respiratory organs. A healthy child drinks continuously without stopping to breathe, and swallows easily.

Examples of Variations in Disease. - If there be any soreness of the mouth the nipple will be held only for a moment and then dropped with a cry of pain. When the throat is affected in infants, swallowing is performed with a gulp, an expression of pain passes over the face, and no more efforts are made than required to satisfy the cravings of hunger. Older children, under similar circumstances, drink little and refuse solid food.

An infant suffering from the oppressed breathing of pneumonia or severe bronchitis, seizes the nipple with avidity, swallows quickly several times and then pauses for breath. In older children the act of drinking, which should be continuous, is interrupted in the same way.

If the finger be put into the mouth of a healthy baby it will be vigorously sucked for some little time. Diminution of this act of suction during a severe illness is a sign of danger; its reestablishment a good omen. In conditions of stupor it is noticeably absent.