The „falsetto is a peculiar modification of voice, differing from the ordinary or chest voice, not only in the higher pitch of the notes, but also in their quality. The theory of its production is still an open point, into which we have not space to enter further than to remark that, according to prof.Wheatstone, falsetto notes are to be explained by sup posing that "the column of air in the trachea may divide itself into harmonic lengths, and may produce a reciprocation of the tone given by the vocal ligaments." The pressure of the air within the trachea during the production of voice is very considerable. From observations made by Oagniard-Latour on a man with a fistulous opening in the trachea, it was found that, when the patient called out at the top of his voice, the pressure was equal to that of a column of water 38 in. in height when he spoke at his usual pitch, to one of 5 in.; and, when he sang in a high note, to one of about 8 inches. The glottis has been well chosen by Dr. Carpenter to illustrate the minute precision with which the degree of muscular contraction can be adapted to the desired effect. The musical pitch of the tones produced by it is, as we have shown, regulated by the degree of tension of the elastic vocal ligaments. Their average length, in a state of repose, is an inch; while in the state of greatest tension it is about difference being thts one-fifth of an inch; while in the female the respective lengths are and respectively—the difference being thus about one-eighth. of an inch. Now the natural compass of the voice, in persons who have cultivated the vocal organ, is about two octaves, or 24 semitones. Within each semitone an ordinary singer could produce at least 10 distinct intervals (the celebrated Mine. Mara could sound 100 different intervals between each tone, the compass of her voice being 21 tones), so that 240 is a very moderate estimate of the number of different states of tension of the vocal cords, every one of which can be produced at will; and the whole variation in the length of the cord being not more than one-fifth of an inch, even in man, the variation re quired to pass from one interval to another will not be more than of an inch (while in such a case as that of 31me. Mara the distance would be reduced to of an inch).
In the production of vocal sounds, the delicate adjustment of the muscles of the larynx, which is requisite to the evolution of determinate tones, is directed by the sense of hearing, being originally learned under the guidance of the sounds actually produced; but "being subsequently effected voluntarily, in accordance with the mental conception of the tone to be uttered, which conception cannot he formed unless the sense of hearing has previously brought similar tones to the mind. Hence it is that persons who are born deaf are also dumb. They may have no malformation of the organs of speech, but they are inevahle of uttering distinct vocal sounds, or musical tones, because they have not the guiding conception, or recalled sensation, of the nature of these. By long training, however, and by imitative efforts directed by muscular sensations in the larynx itself, sonic persons thus circumstanced have acquired the power of speech; but the want of a sufficiently definite control over the vocal muscles is always very evident in their use of the organ."—Op. cit., p. 556. A fund of interesting matter in connection with this subject may be found in Dr. Kitto's Lost Senses. Although not born deaf, he became completely so in early childhood, in consequence of an accident. His voice became similar to that of a person born (leaf and dumb, and taught to speak. It was observed that the words which he had been accustomed to use before his accident, were still pronounced as they had been in childhood, the muscular movements concerned in their production having been still guided by the original audi tory conception, while all the words subsequently learned were pronounced according to the spelling.
The various muscular actions which are concerned in the production of vocal tones, arc commonly regarded as being under the influence of the will. It is, however, easy to show that this is not the case. We cannot, by simply willing to do so, raise or depress the larynx, or move one cartilage of it toward or from another, or extend or relax the vocal ligaments; although "we can readily (10 any or all of these things by an act of the will, exerted for a specific purpose. We conceive of a tone to be produced, and we will to produce it; a certain combination of the muscular actions of the larynx then takes place, in most exact accordance with one another, and the predetermined tone is the result. This anticipated or conceived sensation is the guide to the muscular movements, when as yet the utterance of the voice has not taken place; but while we are in the act of speaking or singing, the contractile actions are regulated by the present sensations, derived from the sounds as they are produced." From these remarks, in which Dr. Carpenter has placed a very difficult subject in as clear a light as the subject admits of, it follows that the muscular actions which arc concerned in the production and regulation of the voice, are clue to an automatic impulse, similar to what occurs in the movements of the eyeball, and in many other cases that might be adduced. There cannot be a doubt that the simple utterance of sounds is in itself an instinctive action; although the combination of these sounds into music or into articulate language, is a matter of acquirement. • Having explained the way in which the larynx produces those tones of which tho voice fundamentally consists, and the sequence of which becomes music, we conic to the subject of speech, which consists, in the modification of the laryngeal tones by other organs superior and anterior to the larynx (as the tongue, the cavity of the fauces, the lips, teeth, and palate, with its velum and the uvula acting as a valve between the throat and nostrils), so as to produce those articulate sounds of which language is formed. The organ of voice is thus capable of forming a large number of simple sounds, which may be combined into groups, forming words. Vocal sounds are divided into vowels and consonants. When a vowel is pronounced what happens? This question is thus answered by prof. Max " Breath is emitted from the lungs, and some kind of
tube is formed by the mouth, through which, as through a clarionet, the breath has to pass before it reaches the outer air. If, while the breath passes through the vocal cords. these elastic lamina are made to vibrate periodically, the number of their vibrations determines the pitch of our voice, but it has nothing to do with its timbre, or vowel. What we call vowels are neither more nor less than the qualities, or colors, or timbre. of our voice, and these are determined by the form of the vibrations, which form, again, is determined by the form of the buccal tube."—Lectures on tke Science of Language, 2d series, p. 116. This writer enters very fully into the various configurations of the mouth requisite for the formation of the different vowels. (1.) In pronouncing u (the vowels are all understood to be pronounced as in Italian), we round the lips, and draw down the tongue, so that the cavity of the mouth assumes the shape of a bottle without a neck. t2.) If the lips are opened somewhat wider, and the tongue be somewhat raised, we hear the o. (3.) If the lips are less rounded, and the tongue somewhat depressed, we hear the 4 of the northern languages (as in august). (4.) If the lips are wide open, and the tongue in its natural flat position, we hear a. (5.) If the lips are fairly open, and the back of the tongue raised toward the palate, the larynx being raised at the same time, we hear the sound e. (3.) If we raise the tongue higher still, and narrow the lips, we hear i. The buccal tube lucre represents a bottle with a very narrow neck, of no more than six centi meters (or about 2i in.) from palate to lips. Diphthongs arise when,instead of pronounc ing one vowel directly after another with two efforts of the voice, we produce a sound during the change from one position to the other, that would be required for each vowel. Though the tube of the mouth thus modified by the tongue and lips is time chief agent in the production of vowels, Czermak has proved that the return palati is changed in position with each vowel, and that it is lowest for a, and rises suc cessively with e, o, a, and i, when it reaches its highest point. He likewise found that She cavity of the nose is more or less opened during the pronunciation of certain vowels. Languages might have been formed entirely of vowels, but the existing words, consist ing solely of bowels, show how unplemant such languages would have been. Some thing else was obviously wanted to supply what Max Muller happily terms the bones of language--namcly, the consonants. These are commonly divided into (1) those which require a total stoppage of the breath at the moment previous to their being produced, and which cannot, therefore, be prolonged; and (2) and those in pronouncing which the interruption is partial, and which, like the vowel sounds, can be prolonged at pleasure.. The former arc termed explosive, and the latter continuous, consonants. In pronouncing the explosive consonants, the posterior openings of the nostrils are completely closed, so as to prevent the passage of air through the nose, and the current may be checked in the mouth in three ways—viz. (a) by the approximation of the lips; (b) by the approxima tion of tin. point of the tongue to the front of the palate; and (c) by the approximation of the middle of the tongue to the arch of the palate. The letters b and p are pronounced_ by the first of these modes; d and t by the second; and g (hard) and k, sounded as,key, by the third; the difference between b, d and g, on the one hand, and p, t and k, depends upon the approximating surfaces being larger, and the breath being sent through them more strongly at the moment of opening in the former than in the latter group. The continuous consonants may be subdivided into three classes, according to the degree of freedom with which the air is allowed to escape, and the compression which it conse quently experiences. In the first class no air paSses through the nose, and the parts of the mouth that produce the sound are closely approximated, so that the compression is considerable. This is the case with v and f, z and s, d and t, th, sh, etc., the movement of the tongue being also concerned in the production of several of these sounds. In the second class, including m, a, 1, r, the nostrils are not closed, and, consequently, the air is scarcely at all compressed. In pronouncing m and n, the breath passes through the nose alone; in is a labial, like b, but the latter is formed with the nose closed. Hence the pas sage of m to b (as in lamb) is easy; so also is that from n to t, or from -a to g, as is seen in the frequent combination of at and 179 in most languages. The sounds of l and 9' (let ters which Max Muller places in a special group under the name of trills) are produced, according to Helmholtz, as follows: "In pronouncing r, the'stream of air is periodically entirely interrupted by the trembling of the soft palate, or of the tip of the tongue, and we then get an intermittent noise, the peculiar jarring quality of which is produced by these very intermissions. In pronouncing 1, the moving soft lateral edges of the tongue produce, not entire interruptions, but oscillations in the force of air."—Die Lehre von den Tonempfindungen, 1863, p 116. The third class contains sounds which scarcely deserve to be called consonants, since they are merely aspirations, either simple, or modified by an elevation of the tongue, causing a slight obstruction to the passage of air, and an increased resonance in the back of the mouth. The present h and.the Greek x are examples of these sounds. The method of pronouncing these sounds is very fully discussed in Max Milller's lectures, 2d series, pp. 127-136.
For further details, the reader is referred to the admirable chapter on "Voice and Speech" in Carpenter's Human Physiology, and to Max Milller's Lectures on the Science of Language (from both of which we have borrowed largely in this article), to Mr. Bishop's article " Voice " in the Cyclopirdta of Anatomy and Physiology; and the various works of Funke, Helmholtz, BrUcke, Czermak, Du Bois Raymond, etc., mentioned by Max Midler in his- chapter on "the Physiological Alphabet."