396 



VOICE AND SPEECH. 



plate, however, is so sensitive that every detail can be recorded, 

 and as a result of its application to the physiology of the larynx, 

 ranch that was regarded as established has been demonstrated to 

 be false : just as the older ideas of the form of a lightning-flash 

 have been entirely changed by instantaneous photography. 



The difficulties to be overcome in photographing the larynx so 

 as to show the changes during voice-production are many, among 



FIG. 218. Apparatus used in photographing the larynx. 



them being the fact that it is only in certain individuals that the 

 vocal bands can be seen throughout their whole length. This is 

 very well shown in Fig. 220. In No. 1 the insertions of the 

 vocal bands into the thyroid cartilage are so exposed as to be sus- 

 ceptible of being photographed ; in No. 2 these are covered by 

 the anterior wall of the larynx, and it would therefore be impos- 

 sible to determine in such a larynx whether the vocal bands were 

 lengthened or shortened in passing from one register to another, 



