Page:Popular Science Monthly Volume 9.djvu/411

Rh of its activity. At present he is engaged in studying the phenomena of voice in the larger animals. As for birds, it is to he hoped that soon we shall understand the organic peculiarities in virtue of which they are able to talk or to sing. Doubtless before long we shall discover the relations subsisting between life-conditions, physical powers, and psychological faculties.

In all those communities which have attained a high degree of intellectual culture, the explanation of natural phenomena has ever more or less engaged the attention of the best minds. Among the ancients we observe a manful effort to discover the secret of the human organization. The origin of speech and of song was unquestionably a subject of profound inquiry for them. Galen, the last and the most famous of the ancient physicians, wrote a description of the larynx, and this description is the work of a master who recognizes the high importance of the work he is engaged in. Since the time of the Renaissance anatomists have been studying the minutest details, and physiologists experimenting. Thus everything was ready for new discoveries, so soon as it should be possible to place before the eye the performance of the instrument used by the singer. It would be difficult, without some knowledge of the vocal apparatus, to understand how the sounds are produced, and hence we will briefly describe those portions of the respiratory organs in which the voice is formed.

The trachea, which is the passage for air between the mouth and the lungs, ascends from the chest to the middle region of the neck; it is made up of cartilaginous rings. At its lower extremity it branches out into two tubes, which are divided and subdivided into numerous ramifications: these are the bronchi, which terminate in the lung-cells. At the upper extremity of the trachea is the larynx, appearing like an angular box, and crowning the trachea like the capital on a column. Cartilages connected by ligaments give considerable strength to the walls of the larynx. Internally these walls have a lining of mucous membrane, which forms folds known as the vocal cords, or better, lips. Under the action of special muscles these folds separate from one another, are elongated or shortened, or become tense, and hence the differences of sound. The cartilages are four in number: two on the anterior surface of the box and two on the sides. In advanced age these cartilaginous plates ossify; the suppleness of the larynx is then greatly diminished, and the voice loses the power of modulation which it possessed in the period of youth. One of the cartilages, which has the form of a ring, is much higher behind than in front. This ring, being firmly fixed upon the first ring of the trachea, serves to support the various parts which constitute the larynx. The largest of these parts shields, as it were, the front of the vocal apparatus: it consists of a plate of cartilage bent into a V-shape, with the point of