f 8$ OBSERVATIONS ON THE d ANNEX. 



ptl^er at a very considerable distance, especially 

 by night. To obviate, therefore, the difficulty 

 of the former, and to produce the desired effect 

 of the latter, nature has b^en abundantly kind in 

 providing this class of animals with a passage 

 from the lungs, to a capacious magazine for 

 air, not only for the purpose of temporary respira- 

 tion, but as a kind of reservoir for certain exi- 

 gencies ; and in particular, that of supplying the 

 instrument of sound with a sufficient quantity of 

 it to be expelled with force through the larynx. 



No one who has a previous knowledge of the 

 size and construction of the lungs, can have ob- 

 served the great exertion of a cock in the act of 

 crowing, without being convinced, that the air, 

 requisite for so strong and continued a sound by 

 one expiration, could not be contained in that 



part/. , " / ' > : ' ;fv ^^l^^^^^^te^P 



If a duck or a goose is attended to when the 



usual cry is emitted, it will be evident, that the 

 pressure of the abdomen propels the air which is 

 therein contained, with much force into the an- 

 terior part of the body, which, with what is there 

 already not being able to escape through the 

 trachea, not only inflates the cellular membrane 

 about the breast to an unusual size, but, by com- 

 pression, rushes with violence through the larynx* 

 and produces a sound more or less intense, in 

 proportion as the muscles are more or less ex- 

 erted. 



