276 ANATID^E. 



the windpipe. The column of air on the right side in the 

 bird, and in the representation, goes direct from the right 

 lobe of the lungs to the tracheal tube ; but the column of 

 air on the left side, on passing through the bronchial tube, 

 is opposed by the descending edge, and being divided by 

 it, a portion is sent in circles round the inner surface of the 

 cavity before it becomes united with the air from the other 

 lobe in the tube common to both. A compound tone of voice 

 is thus produced by which wild-fowl shooters can distinguish 

 males from females, of the same species, in the darkest 

 night, whenever the birds utter their note, and this they 

 frequently do, apparently for the purpose of keeping 

 together. Gilbert White of Selborne, with his usual dis- 

 crimination, says, in his forty-third letter to Daines Bar- 

 rington, which is devoted to the consideration of the notes 

 and language of birds, u among Ducks the sexual distinction 

 of voice is remarkable ; for, while the quack of the female 

 is loud and sonorous, the voice of the Drake is inward, and 

 harsh, and feeble, and scarce discernible." 



The resemblance to the reed or other mouth-piece, and 

 the edge opposed to its inner orifice, to produce vibration, 

 in some musical wind instruments, will be obvious. 



