4:46 HANDBOOK OF PHYSIOLOGY. 



duced only with the natural voice, the highest with the falsetto only; the 

 notes of middle pitch can be produced either with the natural or falsetto 

 voice; the two registers of the voice are therefore not limited iii such a 

 manner as that one ends when the other begins, but they run in part 

 side by side. 



Method of the Production of Notes. The natural or chest-notes, 

 are produced by the ordinary vibrations of the vocal cords. The mode 

 of production of the falsetto notes is still obscure. 



By Miiller the falsetto notes were thought to be due to vibrations of 

 only the inner borders of the vocal cords. In the opinion of Petrequin 

 and Diday they do not result from vibrations of the vocal cords at all, 

 but from vibrations of the air passing through the aperture of the glot- 

 tis, which they believe assumes, at such times, the contour of the em- 

 bouchure of a flute. Others (considering some degree of similaritv 

 which exists between the falsetto notes and the peculiar tones called har- 

 monic, which are produced when, by touching or stopping a harp-string 

 at a particular point, only a portion" of its length is allowed to vibrate) 

 have supposed that, in the falsetto notes, portions of the vocal ligaments 

 are thus isolated, and made to vibrate while the rest are held still. The 

 question cannot yet be settled; but any one in the habit of singing may 

 assure himself, both by the difficulty of passing smoothly from one set 

 of notes to the other, and by the necessity of exercising himself in both 

 registers, lest he should become very deficient in one, that there must be 

 some great difference in the modes in which their respective notes are 

 produced. 



The strength of the voice depends partly (a) on the degree to which 

 the vocal cords can be made to vibrate; and partly (b) on the fitness for 

 resonance of the membranes and cartilages of the larynx, of the pari- 

 etes of the thorax, lungs, and cavities of the mouth, nostrils, and com- 

 municating sinuses. It is diminished by anything which interferes with 

 such capability of vibration. 



The intensity or loudness of a given note with maintenance of the 

 same "pitch," cannot be rendered greater by merely increasing the force 

 of the current of air through the glottis; for increase of the force of the 

 current of air, cceteris paribus, raises the pitch both of the natural and 

 the falsetto notes. Yet, since a singer possesses the power of increasing 

 the loundness of a note from the faintest "piano" to "fortissimo" 

 without its pitch being altered, there must be some means of compen- 

 sating the tendency of the vocal cords to emit a higher note when the 

 force of the current of air is increased. This means evidently consists 

 in modifying the tension of the vocal cords. When a note is rendered 

 louder and more intense, the vocal cords must be relaxed by remission of 

 the muscular action, in proportion as the force of the current of the 

 breath through the glottis is increased. When a note is rendered fainter, 

 the reverse of this must occur. 



