is large, and in whom the dimensions of the larynx are considerable, presents those circumstances, which are the most favourable to the intensity of the voice. But if this person become sick, and his strength reduced, his voice will lose much of its intensity, for this simple reason, that it can no longer expel the air from the chest with great force. Children, women, and eunuchs, in whom the larynx is proportionally smaller than those in adult men, have also naturally the voice much less intense than his. In the ordinary production of the voice, it results from simultaneous movements on both sides of the glottis. If one of these sides lose the faculty of exciting vibrations in the air, the voice will necessarily lose half its intensity, supposing the expiratory force to remain the same. We may satisfy ourselves on this point, by dividing one of the nerves which go to the side of the glottis, or by examining the voice of a person attacked with complete palsy of one side.

Each individual possesses a peculiarity of voice, by which he is as readily known as by his face, and of course this peculiarity is infinite in its modifications. The precise circumstances on which this depends are far from being well understood; but the female voice, and that of children and eunuchs, is generally found connected with a peculiarly soft state of the cartilages of the larynx. The

masculine note of the voice which is sometimes observed in females, seems, on the contrary, to be connected with a hard and bony state of these cartilages, and particularly the thyroid.

NATURAL AND ACQUIRED VOICE.

The only natural voice is that which is known by the name of a cry, being a sound produced by the larynx, and susceptible of variety, both in tone, intensity, and note. It is easily distinguished from all vocal sounds; but, as its character depends upon its note, it is impossible to explain the reason of the difference between it and all other vocal sounds. All men who have not entirely lost their voice, are capable of uttering cries,-the new-born infant and the decrepit old man; the savage and the civilized man; those who have been dumb from birth, and idiots.

Crying, therefore, depends essentially on the organs, and is employed to express strong feelings, either pleasant or painful. The several wants and passions, however, not being connected with organization, have no peculiar cries. Cries are generally the most intense sounds which the organ is capable of forming, often wound the ear, and act strongly by sympathy on those who hear them: they are a kind of language common to most animals, and nearly the only one which they possess. The voice can be greatly modified by imitation;

and all such modifications may be justly denominated an acquired voice, which is exceedingly different in character from the natural voice of crying. A deaf child cannot imitate sounds, and therefore can never possess this acquired voice. Since, therefore, the voice is the result of hearing, and of an intellectual effort, it cannot be developed, unless both these conditions exist. Children who are deaf from birth cannot form any idea of sound; and idiots are not capable of establishing any relation between the sounds which they hear and those which they are capable of producing, and of course can have no voice,—although in both the vocal apparatus may be fitted to form and modify sounds, as well as in those individuals whose conformation is the most perfect. For the same reason, those individuals (such as Peter the wild man) who have been improperly called savages, from their having wandered alone in a forest from their infancy, do not possess voice, because, in this insulated and solitary state the understanding does not sufficiently develope itself, from want of necessity for mental exertion.

CHANGES OF THE VOICE ACCORDING TO AGE.

Before birth, and in the new-born infant, the larynx, compared with the adjacent parts, is proportionally very small. The cartilages are also

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flexible, and are far from possessing the consistence which they afterwards acquire. The larynx preserves these characters until about the period of puberty; at this time, a general revolution takes place in the animal economy. The rapid increase of nutrition causes very considerable changes, and particularly in the organs of the voice. The great increase in the nutritive powers is first apparent in the muscles; afterwards, but more slowly, it is manifested in the cartilages, when the general form of the larynx becomes modified. The thyroid cartilage is developed in front, but much more strongly in the male than in the female; from which circumstance the vocal chords are considerably lengthened, and this is more worthy of remark than the general enlargement of the glottis, which takes place at the same time.

We may remark, that in the change which takes place at puberty, every part that is changed does not always harmonize with the rest: some parts become more tense, others less and yield more easily; some are more relaxed, others more contracted. We may judge of the effect that may be produced by such changes, from the remark of M. Dodart, that a variation in the capacity of the glottis, not exceeding the fifty-fourth part of a silkworm's thread, or one three hundred and fiftyfourth part of a hair, will occasion a difference of

tone. Time, however, and the exercises which we shall afterwards point out, will usually triumph over these discrepancies, wherever they exist, in a few months.

At this period, the male voice sometimes acquires in a few days, and sometimes more suddenly, a grave note essentially different from what it exhibited before, and generally falls an octave or a fifth. In some cases the voice is nearly lost, and does not entirely return for some weeks. Frequently there remains, for a time, a remarkable hoarseness; and young men often form very acute sounds when they intend to produce grave ones, from the voice being dissonant, and untrue to itself, and irregularly alternating from harsh to shrill. This state of things continues frequently for a year, after which the voice gets its natural note, which continues through life: though we sometimes meet with individuals, who at this time lose for ever the faculty of singing; and others, whose voices before this period were rich and extensive, afterwards become indifferent and limited.

The gravity which the voice acquires depends evidently on the developement of the larynx, and especially on the lengthening of the vocal chords. As these parts cannot extend backwards, they are lengthened in front; and this causes the prominence