OF THE HUMAN VOICE. 
571 
rior portion of the arytenoid cartilages and the thyroid, with all the parts 
above the inferior vocal cords, are removed, in order to leave the sides of 
the vocal cords free to admit the application of the compressor. 
aa. The bases of the two arytenoid cartilages secured by a pin, and 
bound together. 
b. Thyroid cartilage. 
c. Cricoid. 
d. Vocal cords. 
e. Thyro-arytenoid muscles. 
PLATE XXXII. 
Fig. 8. Apparatus for experiments on the chest voice, under a graduated lateral com- 
pression of the vocal cords by means of the compressor. 
Fig. 9. Represents the head and vocal organs prepared for experiments. The cervical 
vertebrae are removed, and the oesophagus opened behind the arytenoid 
cartilages, which are fixed together by a strong pin and ligature ; the latter 
is brought through the opening, which is then firmly sewed together, and 
the lower opening of the oesophagus is also closed up. The larynx is 
laid bare, and the superior portion of the thyroid cartilage carefully re- 
moved so as not to injure the mucous membrane of the larynx. The parts 
thus prepared are firmly fixed against the column, to which the arytenoid 
cartilages are also attached by the cord which binds them together. The 
trachea is connected with a pipe and bellows for the supply of air. 
a. The trachea. 
b. The os hyoides. 
c. The cricoid cartilage. 
d. Portion of the thyroid cartilage remaining for the attachment of the 
cords e, by means of which the vocal cords may be extended. 
Fig. 10. Compressor used in the apparatus, fig. 9, on a larger scale. 
4 e 2 
