Page:Popular Science Monthly Volume 9.djvu/413

Rh the result of a strange confusion of ideas. The ancients observed in the larynx "organs resembling the mouth-pieces of ancient flutes, viz., the parts on the right and left, which meet and regulate the passage of the air." Later, the term denoting the folds which bound the orifice was used to designate the orifice itself. This error has been confirmed by the usage of centuries, but yet it is better to give, as Mandl does, to the space between the vocal lips, the name of glottic orifice, or orifice of the glottis. The superior portion of the larynx is the vestibule communicating directly with the back part of the mouth. Above the entrance to the vestibule and back of the tongue, a fibrocartilaginous plate, the epiglottis, defends the passage. Under ordinary circumstances, the epiglottis stands vertical, presenting no obstacle to the free passage of air in both directions. When depressed, it covers the opening. Every one, from personal experience, is familiar with the painful sensation produced by the entrance of liquids or solids into the respiratory passages. Apparently the epiglottis closes up this passage during the act of swallowing, but on this point we have no certainty; we cannot observe the act of deglutition, and we know that the vocal cords may be moistened by liquids without causing inconvenience.

Like every other organ, the larynx presents considerable individual differences. A good development of the larynx indicates a strong, deep voice. In childhood this apparatus undergoes very little change, but at the period of adolescence it grows very rapidly, the effect being an alteration of the voice, very notable in boys, but inconsiderable in girls. In all cases, without regard to stature, the larynx is smaller in women than in men. Its angles are less salient, its muscles weaker, its cartilages thinner, and more supple: the sharp notes of the instrument are the evidences of these peculiarities of conformation. Though our general knowledge of the vocal organs is very positive, nevertheless we are unable to determine the characters of the voice by simply examining the larynx, for it is impossible to compare in all their details those instruments whose good or bad qualities are known.

The vocal apparatus is perfected by the addition of the cavities which produce resonance, viz., the pharynx, the mouth, and the nasal fossæ. The pharyngeal cavity, into which open the œsophagus and the larynx, is continuous with the buccal cavity, a hollow box admirably adapted for articulation. Its shape and size are extremely variable. The cheeks constitute walls which can be compressed or dilated with the slightest effort; the lips, which bound the anterior opening, are perfectly mobile; the tongue can be moved in every direction; in the rear, the velum palati, or soft palate, suspended from the palatal arch, is supple and contractile. This veil of the palate is simply a fold of mucous membrane, separating the buccal from the pharyngeal cavity; it also extends to the nasal fossæ, which it closes; it terminates