80 TRESPASSERS UPON THE AIR. 



its plumage uniformly deep black ; its beak and 

 legs white. 



f ' The example we obtained was shot in the wing 

 and brought on board alive, fighting savagely with its 

 beak and feet. 



" With a view to preserving its plumage uninjured, 

 I endeavoured to destroy the bird by compressing its 

 windpipe, but found that as the breathing became 

 laborious, a loud whistling sound was emitted from 

 some part of the. body, and, upon close investigation, 

 found that the bone (humerus) of the wing, which was 

 fractured across, projected through the skin, and ad- 

 mitted within its tube a forcible current of air when- 

 ever the lungs made an effort at respiration. 



"The bird was, in fact, breathing through its 

 broken wing ; and so sufficient was the supply of air 

 which the lungs received through this novel channel, 

 that I was wearied with my attempts to suffocate my 

 prize, and had to destroy it in another manner. 



" The free communication which exists between the 

 air cells of the lungs and the cavities of the bones in 

 birds, offers an easy elucidation of this phenomenon, 

 although such an application of the economy must be 

 regarded as singular/' 



In connection with this subject, I may remind the 

 reader that the bone of an albatross' wing is much in 

 fashion as a pipe stem, being light, strong, and 

 tubular. 



In the Flying Mammalia, this modification of 

 structure is not found, but we shall presently see that 

 in them a similar effect is produced by different 

 means. 



