328 THE VOICE. [BOOK in. 



that some of the fibres of the internal thyro-arytenoid running 

 forward from the processus vocalis and outer surface of the ary- 

 tenoid are inserted into the layer of elastic fibres at varying 

 distances from the thyroid. If some of these bundles were to 

 contract by themselves they might render the front part of the 

 cord tense and the hind part relatively lax, or might modify in 

 particular parts that general tension of the whole cord which was 

 being effected by the crico-thyroid. 



Further, the closure of the glottis, the adduction of the cords 

 may take place in different ways, according as this or that muscle 

 or part of a muscle is being especially used. While the vocal cords 

 are being sufficiently approximated to allow the expiratory blast 

 to throw them into vibrations the cartilaginous glottis may remain 

 fairly open, or may be nearly or be quite closed ; and each of these 

 conditions must affect the voice in a different way. Again, we 

 have seen that the two vocal cords are close together at their 

 insertion into the thyroid, and diverge from the middle line on 

 each side so that the membranous glottis, when the larynx is at 

 rest, is an isosceles triangle. We might infer from this that when 

 the cords are adducted, the glottis must always remain an isosceles 

 triangle with the angle at the apex, next to the thyroid, becoming 

 more and more acute as adduction proceeds, and that the parts of 

 the cords in front, nearer the thyroid, must come into actual 

 contact before the parts behind, nearer the processus vocales, do. 

 But the laryngoscope shews that the form of the membranous 

 glottis is very varied ; it may be open behind and closed in 

 front, or closed both behind and in front and open, even widely 

 so, in the middle, or may be along almost its whole length a 

 slit with parallel sides, and in that case either very narrow, a 

 mere linear cleft, or of appreciable width. And though the 

 exact mechanisms are obscure, we cannot doubt but that these 

 several phases result from special muscular contractions. 



912. We might dwell on other changes which may by help 

 of the laryngoscope be observed in the larynx during the pro- 

 duction of the voice, all shewing that muscular contractions may 

 produce complex and varied changes in the larynx besides simple 

 adduction or abduction and general tension or slackening of the 

 vocal cords ; but we have said enough for our present purpose, 

 which is to insist that in the production of voice the mere dimen- 

 sions of the larynx, and we might add other natural inborn features, 

 serve but as the playground for muscular skill ; it is the latter 

 much more than the former which determines the characters and 

 the powers of the voice. A laryngoscopist, even the most ex- 

 perienced, would probably hesitate from a mere inspection of the 

 larynx to predicate the nature of the singing voice. He could not 

 even predicate the possession of a singing voice of any kind. Of 

 two larynges, provided they were both of normal structure, he would 

 be unable to say which belonged to the man who could and which 



