OF NATURAL HISTORY. xij 



* body, all communicate with the lungs, and are capable of being 

 ' filled with air; and again from thefe the cells of the fternum, ribs, 



* vertebrae of the back and loins, bones of the pelvis, the humeri, 



* the ulna and radius, with the pinions and thigh-bones, can in many 

 ' birds be furnifhed with air *.' 



Thefe fads, which our author candidly acknowledges had been 

 formerly obferved, led him, in the year 1758, to make experiments 

 on the breathing of birds, in order to prove the free communicatioa 

 between the lungs and the feveral parts of the body mentioned 

 above, 



' Firft,' fays he, ' I made an opening into the belly of a cock, 



* and having introduced a filver canula, tied up the trachea ; I found 



* that the animal breathed by this opening, and might have lived ; 



* but, by an inflammation in the bowels coming on, adhefions were 



* produced, and the communication cut off. 



' I next cut the wing through the os humeri, in another fowl, 

 ' and tying up the trachea, as in the cock, found that the air pafled 



* to and from the lungs by the canal in this bone. The fame expe- 



* riment was made with the os femoris of a young hawk, and was 

 ' attended with nearly the lijie fuccefs f.' 



The extreme fingularity of this almofl: univerfal diffufion of air 

 through the bodies of birds, naturally excited a defire to difcover 

 what might be the intention of Nature in producing a ftrudture fo 

 extraordinary. Mr Hunter firft imagined that it might be intended 

 to aflift the ad of flying, by increafing the volume and ftrength of 

 t P the 



* Hunter's Obfervations on certain parts of the Animal Oeconomy, pag. 81. 

 \ Ibid. pag. 82. 



