OF THE LARYNX, AND ITS ACTIONS. 855 



false or upper vocal cords apply themselves to the true vocal cords in front, 

 behind, and to the sides, so that the middle portion of the true cords alone 

 vibrates ; whilst by the contraction of the arytenoidei muscles the cords are 

 brought into close apposition 1 with each other for part of their length, their 

 thin edges only being in vibration in the remainder. It has been pointed 

 out by Mr. Bishop (loc. cit. ), that at the moment of transition from the 

 " chest-voice " to the " falsetto-voice," the crico-thyroid chink, which was 

 closed during the production of the highest note of the former, suddenly 

 opens on the production of the lowest note of the latter; thus indicating 

 that the vocal cords are relaxed in the passage from the one to the other, as 

 must be the case, if, for the production of the same note, they be only put 

 in vibration along a part of their length ; so that it would not seem im- 

 probable that the cause of those differences in the mode of transition which 

 have been already noticed, lies in the differences in the proportional amount 

 of the vocal cords which is thus thrown out of use by the partial approxi- 

 mation of the two lips of the rima glottidis. It is further remarked by Mr. 

 Bishop, that, in the passage from the chest to the falsetto-voice, the larynx 

 descends from its previously elevated position, and gradually rises again 

 with the ascending scale of falsetto notes ; and he mentions a case of double 

 falsetto, in which a third register existed, and in which the relaxation of the 

 vocal cords and the descent of the larynx were observed at its commence- 

 ment, as at the commencement of the second or ordinary falsetto register. 2 

 The pressure of the air within the Trachea during the production of voice 

 is considerable. Caguiard de Latour observed in a man with a tracheal 

 fistula, that the pressure indicated by a manometer when the patient called 

 out at the top of his voice, was equal to a column of water 38 inches in 

 height; when he spoke at his usual pitch, to one of 5 inches; and when he 

 sang a high note, to one of about 8 inches. The deepest notes the human 

 Larynx is capable of producing have about 80 double vibrations in the sec- 

 ond, the highest about 992 ; the former occurring in bass, the latter in 

 soprano voices. Donders 3 gives the limits at 44 vibrations, corresponding 

 to the F of the lowest bass voice, and 1408 for the highest note correspond- 

 ing to the highest/'" of the soprano, which includes five octaves. 



701. The various muscular actions which are employed in the produc- 

 tion and regulation of the Voice, are called forth by an impulse which has 

 been shown ( 537, 542) to be really automatic in its operation, and to be 

 completely under the influence of guiding sensations, although usually orig- 

 inating in a Volitional determination, or giving expression to Emotions or 

 simply to Ideas. This, however, has been proved to be also true of all Vo- 

 litional movements; so that the production of vocal tones constitutes no real 

 exception. It may be safely affirmed that the simple utterance of sounds is 

 in itself an Instinctive act; although the combination of these, whether into 

 music or into articulate language, is a matter of acquirement, which is much 

 more readily made by some individuals than by others. No definite tone 



1 See also Ch. Bataille, Nouv. Keen, sur hi Phonation, Paris, 1861. 



2 An entirely different theory of the falsetto has been given, however, by MM. 

 Petrequin and Diday (Gazette M^dicale, 1844), who consider that the falsetto notes 

 are nut produced by the vibration of the vocal cords, but are really " flute-notes," 

 formed by the vibrations of the column of air to which the rima glottidis then serves 

 as the embouchure. This view harmonizes well with some of the phenomena of the 

 falsetto voice ; but it is open to the objections already stated in regard to the flute 

 theory generally. It may be added that some have attempted to show that the fal- 

 setto depends upon a peculiar action of the parts above the larynx ; but for this doo- 

 trine there is no foundation whatever. 



3 Dr. Moore's Translation in Humphry and Turner's Journ. of Anat. and Physi- 

 ology, vol. i, 1867, p. 173. 



