ACTIONS OF THE LARYNX. 463 



cricoid cartilages, as formerly described ( 603).* A very important adjunct 

 to the production of the higher notes, has been pointed out by Muller, as 

 being afforded by the modification in the space included between the two 

 sides of the thyroid cartilage, which is effected by the thyro-arytenoidei. He 

 had experimentally ascertained, that the introduction of a hollow plug into the 

 upper end of the pipe beneath his artificial larynx (and therefore just below 

 the reed), by diminishing its aperture, produced a considerable elevation of 

 the tone. The action may be imitated in the human larynx, when made the 

 subject of experiment, by compressing the thyroid cartilage laterally; and in 

 this manner, the natural voice could be made to extend through a range, that 

 could otherwise be only reached by a falsetto. 



610. The strength of the tone produced in the larynx, is much increased 

 by the resonance of the elastic tissue, which it contains in various other parts ; 

 but still more, perhaps, by that produced by the air in the trachea, bronchi, 

 and pulmonary cells. This comes to be of great importance in the pheno- 

 mena of auscultation. The aerial resonance is loudest where any large body 

 of air is collected together, as in the trachea, the larger bronchi, an emphyse- 

 matous dilatation, or a cavity resulting from tubercular softening. On the 

 other hand, solidification of the pulmonary tissue will produce a resonance of 

 a somewhat different kind. The influence of the prefixed and superadded 

 tubes, in modifying the tones produced by the Human larynx, has been found 

 by Prof. Muller not to be at all comparable to that which they exercised 

 over the artificial larynx ; the reason of which difference does not seem very 

 apparent. It appears, however, that there is a certain length of the prefixed 

 tube, as there is a certain distance of the vibrating laminae, and a certain 

 length or form of the tube above, which is most favourable to the produc- 

 tion of each note ; and the downward movement of the whole vocal organ, 

 which takes place when we are sounding deep notes, and its rise during the 

 elevation of the tones, have been supposed to have the purpose of making this 

 adjustment in the length of the trachea; but this requires the supposition, 

 that the real length of the trachea is shortened whilst it appears extended, 

 for which there seems no foundation. It is considered by Mr. Wheatstone, 

 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 

 ( 560) ; and in this manner he considers that the falsetto notes are to be 

 explained. It may be added, that the partial closing of the epiglottis seems 

 to assist in the production of deep notes, just as the partial covering of the 

 top of a short pipe fixed to a reed will lower its tone ; and that something of 

 this kind takes place during natural vocalization, would appear, from the re- 

 traction and depression of the tongue which accompany the lowering of the 

 front of the head, when the very lowest notes are being sounded. The arches 

 of the palate and uvula become contracted during the formation of the higher 

 tones ; but no difference can be perceived in their state, whether these tones 

 be falsetto or not; hence it would appear that they have no concern in this 

 peculiarity ; and the purpose of their increased tension is probably to main- 

 tain their power of resonance. The experiments of Savart have shown, that 

 a cavity which only responds to a shrill note, when its walls are firm and dry, 

 may be made to afford a great variety of lower tones, when its walls are 



That the falsetto voice differs in some essential particular from the natural, is evident 

 from this, that many persons who possess a considerable range of both, are yet unable to 

 unite them, so as to sing through the whole scale without a marked interruption. Thus a 

 gentleman of the Author's acquaintance has a bass voice, ranging from the lowest D of the 

 Square Piano to the second D above ; and a falsetto ranging from the A below this to the E 

 of the octave above, so as to give a compass of more than three octaves on the whole ; yet 

 the two registers cannot be smoothly blended. 



