HEAD REGISTER. 1213 



been followed which is, on the whole, the most generally accepted. As 

 regards the action of the larynx, however, during the different registers, 

 though there is some agreement as to the principal changes which occur, 

 many parts are as obscure as the amount of literature on the subject is 

 large. 



Lehfeldt, 1 when experimenting upon larynges removed from the 

 dead body, found, by accident, that when a weak blast of air was 

 driven through the glottis, the pitch of the note produced was higher 

 than when the blast was strong. From this discovery he inferred 

 that the falsetto (thin) register was produced by a weak current of 

 air, while a strong current was necessary for the production of the 

 chest register. He further maintained that the reason why the note 

 produced by the strong blast was deeper than that produced by the 

 weak one, was because in the first case the cords were made to 

 vibrate in their whole extent, while the weak current was unable to 

 effect this. 



Johannes Miiller 2 adopted this view, and its truth is still maintained 

 by some authorities. Lehfeldt further supposed that the outer fibres of 

 the thyro-arytenoid muscle might hinder the outer portions of the cords 

 vibrating, while the inner portions were free to vibrate. There is nothing 

 inconsistent in this from an acoustical point of view. Oertel's 3 view, 

 promulgated in recent times, is somewhat akin to this ; he holds that 

 when the falsetto voice is produced, nodal lines are formed in the vocal 

 cords, parallel to their edges. 



Garcia, 4 from observations with the laryngoscope, which he intro- 

 duced, held that, in the lower part of the chest register, the whole of 

 the cord, along with the vocal process of the arytenoid cartilage, is 

 thrown into vibration ; while, as the voice ascends in pitch, only the 

 ligamentous portion of the cord vibrates, the vocal processes being in 

 contact. Behnke, 5 on the other hand, maintains that the vocal processes 

 of the arytenoid cartilages do not vibrate at all during phonation. In 

 recent years, however, it has been definitely shown that these cartila- 

 ginous structures do partake in the vibration of the cord. Hodgkinson 6 

 insufflated finely powdered indigo into the larynx, and, by observing the 

 positions which it assumed on the cord during phonation, he was able 

 to demonstrate the fact that, in the deeper note of the lower register, 

 the vibrating margin extended from the thyroid cartilage in front to a 

 point behind the junction of the ligamentous and cartilaginous portions 

 of the cord. Hodgkinson's experiment further disproved the assertions 

 of some authorities, who maintain that contact of the vocal processes 

 is essential for phonation. In this respect Hodgkinson's view is in 

 agreement with that of Wesley Mills. 7 



As regards the mechanism of the middle register, observers are fairly 

 unanimous upon one point, namely, that the vocal processes of the 

 arytenoid cartilages are in contact throughout. As regards minor 

 points, opinions vary considerably ; this may be due to the fact that 

 the mechanism itself differs in individuals. 



2 "Physiology," translated by Baly, London, 1837-42. 



1 "Inaug. Diss.,"1835. 

 gy, 



3 " Ueber d. Median, des Brust- u. Falsett- Registers," Stuttgart, 1882. 



4 "Beobacht. ueber d. menschl. Stimme," Monatschr.f. Ohrenh., Berlin, 1878, Nos. 1 to 6. 



5 " Mechanism of the Voice," 1880, p. 88. 



6 Brit. Med. Journ., London, 1895, vol. ii. p. 482. 



7 Proc.Am. Ass. Adv. Sc., 1882. 



