Page:Popular Science Monthly Volume 64.djvu/272

268 occasionally omitted as in the words 'heir,' 'humor,' etc., and infrequent in the French and quite softly when pronounced.

The aspirate, which is sounded without approximating the vocal cords, brings us to the whisper in which we have all the elements of speech without the initial vibrations of the vocal cords. That these are not concerned in the whisper is demonstrated by the fact that persons, suffering from such forms of paralysis that the cords can not be brought together, can whisper, and that even where the vocal cords have been entirely destroyed by tuberculous or other disease, the patient can still whisper without difficulty.

As already stated, the modifications of the vowel sounds for articulate speech are made in the cavities of the mouth, the upper part of the throat and by the nostrils, and are further modified by the position of the teeth, lips and palate. In perfect singing or speaking, we must have all these parts in a normal condition, and where there is no obstruction, defect, congestion or inflammation, there is no interference with the free motion or vibration of the parts concerned in voice production.

The question may be asked how this information about the action of the vocal cords has been learned, since, during life, they are out of sight. The use of a mirror by the throat specialist is now so common that it no longer attracts any comment, although this method of examining the larynx of a living subject is yet comparatively recent. The method, however, by means of which these parts are inspected is not so well understood, and it would, therefore, be not without interest to explain it.

The interior of the larynx, being separated from without by its skin and cartilages, is, of course, dark, and must therefore first be illuminated in order to be seen. A small mirror is therefore placed in the back part of the throat, which projects the rays of light downwards into the parts to be inspected. In order to enable the operator to use the same mirror for inspecting as for illuminating the larynx, he fastens to his forehead a concave mirror which reflects the condensed light to the throat mirror, and by means of an opening in the center of the head mirror, he is enabled to see the parts of the throat that are illuminated by the throat mirror. This arrangement, which is comparatively simple, has been the foundation of the science of