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Dr. Croker King made the following communication on 

 the adjustment of the chordae vocales by the oblique aryte- 

 noid muscles : 



" In the course of the following communication, it will 

 appear that a peculiar position of the vocal cords is necessary 

 for the production of a distinct intonation ; and that, if the vocal 

 cords be not brought into this favourable position, the larynx 

 will cease to execute its function as an organ of voice. 



*' The means by which this essential adjustment is eflFected 

 has been a matter of uncertainty and doubt; and the object of 

 this communication is to show that there exists in the human 

 larynx an apparatus of great efficiency, which is capable of ex- 

 ecuting the desired movement with accuracy and precision ; 

 and that, although the muscular fibres which perform this 

 office have been well known to anatomists and physiologists, 

 this special use has not hitherto been assigned to them. 



" The term larynx has been applied by anatomists to a cy- 

 lindrical box, which surmounts the trachea or windpipe, and 

 contains the organ of voice. The box is formed of a resisting 

 material, so that its capacity may not be diminished or ob- 

 literated by the collapse or falling in of the sides, which, were 

 its parietes formed of a flaccid material, would inevitably re- 

 sult from an effort of inspiration. The animal structure used 

 is named cartilage, and there are several distinct pieces of this 

 material in the larynx ; they are connected to each other so as 

 to form articulations or joints, and, appropriate muscles being 

 assigned to them, they can be freely moved upon each other. 



" It is not my intention to occupy the time of the Aca- 

 demy by entering into a detailed description either of the laryn- 

 geal cartilages or muscles, but to confine myself to such notice 

 of the anatomical features of the larynx as is absolutely re- 

 quired to render the particular object of this communication 

 intelligible. 



" The trachea or windpipe is surrounded byastrong ring of 

 cartilage termed the cricoid, which serves as a foundation upon 

 which the superjacent mechanism is erected. Upon the upper 

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