pansion and compression of this capacious organ, the process of breathing is conducted; and by its resonance the voice receives depth and volume.

4. The intercostal muscles at the lower, and

5. The thoracic and pectoral muscles, at the upper part of the chest, serve to dilate and compress it, in the acts of breathing and of utterance.

6. The pleura, a membrane which envelops the lungs, and propagates to their cells the impulse by which these are emptied of their successive supplies of air inhaled at the intervals of speaking or singing.

7. The lungs, a spongy body in the form of lobes, into the cells or little cavities of which the air inhaled in breathing is drawn, and from which it is expelled by the impulse communicated, as mentioned before, by the pleura, and derived from the diaphragm and the abdominal muscles. 8. The bronchi, or two main branches of the trachea or wind-pipe. These two tubes are themselves subdivided into many subordinate and minute ramifications, which serve to distribute to the air-cells of the lungs in which they terthe breath inhaled through the trachea, and to convey that which is expelled from the lungs by the impulsive action of the diaphragm into the trachea, the larynx, and the mouth. One important office of the bronchial ramifications is to vibrate, and thereby aid in rendering vocal the column of air which is emitted from the cells of the lungs.

minate

9. The trachea or wind-pipe, a series of connected cartilaginous or gristly rings, forming the great air-tube, which receives and conducts the breath to and from the lungs, in the acts of inspiration and expiration, and in the function of utterance.

10. The larynx, a cartilaginous box on the top of the trachea, the exterior projection of which is familiarly called the Adam's apple, in allusion to the fabled origin of this part, which was anciently said to have owed its existence

to Adam's fatal offence in swallowing the forbidden fruit. The whole larynx is the immediate seat and general instru ment of vocal sound. The portions of this organ which are immediately concerned in the production of sound are, 11. The cricoid cartilage, situated immediately over the uppermost ring of the trachea, resembling in form a sealring, from which it takes its name, but having the broad part at the back, and the narrow in front. The form and position of this portion of the larynx admit of the eleva tion and depression of its parts, one step in the process by which tone is rendered grave or acute.

12. The arytenoid cartilages so called from their fancied resemblance in shape to a ladle, funnel, or pitcher. These fill up the space at the back of the thyroid and cricoïd cartilages, and are connected with both; while they serve also as points of support and of tension for the vocal ligaments.

13. The thyroïd cartilage, which has its name from its partial resemblance to the form of a buckler or shield, but much bent. Its two main plates form the walls or sides of the larynx; and their size usually determines the capacity of the voice, as we observe, in their comparative smallness in females and children, and their great expansion and projection in men.

The comparative solidity of texture, in all these component portions of the larynx, and in the gristly rings of which the trachea is itself composed, give them the power of rendering the voice compact and sonorous.

14. The vocal ligaments extend across the upper part of the larynx, and form the lips of the glottis, and by their vibration, together with the action of the current of air expelled through the trachea and larynx, produce the phenomena of vocal sound or voice, and, by their tension or remission, the effect of high or low pitch.

15. The glottis, so denominated from the partial resem. blance of its shape to that of the tongue, is a small chink, or opening, which forms the mouth of the larynx. The

opening and the contraction of this portion of the vocal apparatus decide, in part, the gravity or the shrillness of

tone.

All the parts of the larynx are interconnected by ligaments, and by muscles which move in concerted action, so as to expand or contract, raise or lower the whole larynx, and thus enlarge or diminish its capacity, and elevate or depress the pitch of the voice, and increase or diminish its force. The whole interior of the larynx is lined with a continuation of the mucous membrane of the mouth, which imparts to it a vivid sensibility and a unity of action. Hoarseness is the result of the embarrassment or obstruction of this membrane, by the mucous accumulations arising from colds or catarrh, or the injudicious habit of using cold water too freely during the exercise of speaking.

16. The epiglottis, the valve or lid, which, when the larynx is elevated, as in the act of swallowing, covers the glottis or orifice of the windpipe and prevents strangulation. Its usual erect position allows free ingress and egress to the breath. But in some instances of intensely impassioned utterance its pressure against the glottis becomes an additional preparative for the ultimate explosive eruption of voice.

17. At the root of the tongue lies a small crescentshaped or horseshoe-formed bone, called, from its resemblance to the Greek v, the hyoïd, or u-like bone. This member serves, by its firm texture, as a gateway from the trachea and larynx to the mouth, or from the latter to the former. It forms a point of tension for the muscles which connect the larynx with the mouth. Its hard texture enables it to perform this office effectually, and thus to aid in giving pitch in vocal sounds.

18. The thyro-hyoïdean membrane connects the thyroïd cartilage with the instrument just described, and facilitates the functions of both in elevating or depressing the pitch of the voice.

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19. The crico-thyroid ligament attaches, as its name im plies, the cricoïd or the thyroïd cartilage; and (20) the crico-thyroïd muscle facilitates their consentaneous movement, in the production of vocal sound, acute or grave.

21. The pharynx or swallow, situated immediately behind and above the larynx, although not directly concerned in the production of sound, has, by resonant space, a great effect on its character. Persons in whom this organ is large have usually a deep-toned voice; those in whom it is small have comparatively a high pitch. When it is allowed to interfere with the sound of the voice, through negligence of habit or bad taste, it causes a false and disagreeable guttural swell in the quality of the voice.

22. The nasal passages. Through these channels the breath is inhaled in the usual tranquil function of breathing. The innermost part of the nostrils is united into one resonant channel, and opens into the back part of the mouth, behind the "veil," or pendent and movable part, of the palate, which serves as a curtain to part the nasal arch from the anterior portion of the mouth.

Above the valve of

23. The internal tubes of the ears. the orifice of the windpipe, on each side of the root of the tongue, is a small opening, leading to a tube which communicates with the ear, and whose orifice is always opened in the act of opening the mouth. These tubes have a great effect in rendering vocal tone clear and free; as is perceived in the case of obstructions arising from disease, from accident, or from cold, which impart a dull and muffled sound to the voice. "The ear," says an eminent writer on this subject, being formed of very hard bone, and containing the sonorous membrane of the drum, the sound of the voice entering it through the air-tubes must necessarily be increased by its passage along what may be termed the whispering galleries of the ear."

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The effect of these passages, as conductors of vocal sound, may be traced in the fact that the middle and innermost

parts of the nostrils open into several hollows or cells in the adjacent bones of the face and forehead. By this arrangement the whole cavity of the head is rendered subservient to the resonance of the voice. That degree of clear, ringing, bell-like sound, which is so obvious a beauty of the human voice, seems to be dependent on this circumstance. Hence, too, the stifled tone caused by obstruction arising from cold, from accident, from the deleterious effect of snuff-taking, or from malformation of organic parts.

The fault of utterance which is termed nasal tone arises from lowering too far the veil of the palate, the membrane which separates the mouth from the nasal passages, and raising too high the root of the tongue, in producing a vocal sound. The consequence of these errors is that an undue proportion of breath is forced against the nasal passages, and that these organs are at once overcharged and obstructed. Hence the twanging and false resonance which constitutes "nasal tone.

24. The cavity, and more particularly (25) the roof, or ridgy arch, of the mouth, in the anterior part of it, together with (26) the palate, and (27) the veil, or pendent and movable part of the palate, and (28) the uvula, or the terminating tag of the veil of the palate in the back part of the mouth, as well as (29) the upper gum and (30) the teeth, in the fore part of it, all serve important purposes in modifying the sound of the voice, and aiding the function of speech.

The most satisfactory mode of forming a correct idea of these organs is to inspect the interior of the mouth by the use of a looking-glass. In this way the position and action of all these parts in the function of speech may be distinctly observed.

The mouth, by its arched structure, exerts a great influence in moulding the sound of the voice. It serves at once to give it scope and partial reverberation. It gives sweetness and smoothness to tone; as we perceive in contrast