ORGANS OF BREATHING. 55 



rendered buoyant; a considerable portion of the skeleton 

 moreover, as we have shown, being formed into recep- 

 tacles for this light and elastic fluid, of which birds 

 partake in so much greater a degree than most other 

 parts of the creation. In fact, a bird, destined as it is 

 to live in air, may be almost called an absolute air- 

 vessel, so completely does air fill up and circulate 

 throughout its whole frame. While men and other 

 land animals breathe in air through the nostrils alone, 

 .a bird respires through a variety of other channels. A 

 wounded Heron was observed to live a whole day, 

 breathing solely through a broken portion of the wing- 

 bone*. Other experiments have confirmed the fact; 

 the fractured portion of a bone that had been separated, 

 when immersed in soap and water, was observed to emit 

 bubbles from the part nearest the body, proving beyond 

 a doubt that it contained air in considerable quantities. 



The quills of the feathers are also air-vessels, which 

 can be emptied and filled at pleasure. 



There is a bird called the Gannet, or Solan-Goose, 

 which is a beautiful instance of this wonderful provision ; 

 it lives on fish, and passes the greater part of its time 

 either in the air or on the water, even in the most tem- 

 pestuous weather, when it may be seen floating like a 

 cork on the wildest waves. To enable it to do so, with 

 the least possible inconvenience, it is provided with a 

 greater power of filling and puffing itself with air than 

 almost any other bird. It can even force air between 

 its skin and its body, to such a degree, that it becomes 

 nearly as light and buoyant as a bladder. This buoy- 

 ancy, however, entirely prevents its diving after fish: 

 Nature, therefore, has applied a remedy by giving an 

 extraordinary force and rapidity of flight, in enabling 

 the creature to dart down on a shoal from a great 

 height. This velocity is so prodigious, that the force 

 with which it strikes the surface of the water is sufficient 

 to stun a bird not prepared for such a blow, or force 



* Seo Linn&an Transactions, vol. xi. p. 11. 



