Plate IV
THE LARYNX
The illustration on the opposite page shows the upper part of the larynx and the base of the tongue.
During the inspiration of a full breath, or when singing a low note, the Epiglottis lies forward and points upward, as shown in the cut, with the glottis (the passage leading into the windpipe between the vocal cords) wide open.
During the act of swallowing, the epiglottis is turned downward and backward until it touches the Cricoid Cartilage, thus closing the glottis. The cricoid cartilage, which forms the upper part of the framework of the larynx, rests on the "Adam's apple."
The False Vocal Cords are bands of ligament, and take no part in the production of sound.
The True Vocal Cords move during talking or singing, and relax or contract when sounding, respectively, a low or high note. Hoarseness and cough occurring during laryngitis, diphtheria, and croup, are the result of inflammation of the mucous membrane lining the larynx.
PLATE IV
TONSILITIS (Follicular Tonsilitis).—Tonsilitis is a germ disease and is contagious. Exposure to cold and wet and to germ-laden air renders persons more liable to attacks. It is more likely to occur in young people, especially those who have already suffered from the disease and whose tonsils are chronically enlarged, and is most prevalent in this country in spring. The disease appears to be often associated with rheumatism. Tonsilitis begins much like grippe, with fever, headache, backache and pain in the limbs, sore throat, and pain in swallowing. On inspecting the throat (with the tongue held down firmly by a spoon handle and the mouth widely open in a good light, preferably sunlight) the tonsils will be seen to be swollen, much reddened, and dotted over with pearl-white spots.