OF NATURAL HISTORY. 119 



ble howlings. A bird, when lick, ceafes to fing, droops the 

 win or, abftains from food, afTumes a lurid afpect, utters me- 

 lancholy, weak cries, and exhibits every mark of depreiTed 

 fpirits. By this means, animals intimate the afiutance they 

 require, or foften thofe who maltreat them. Their plain- 

 tive cries are fometimes fo afte6ling as to difarm their ene- 

 mies, or procure the aid of their equals. On the other 

 hand, when animals are pleafed or carefTed, they difcover, by 

 their countenance, by theiir voice, by their movements, une- 

 quivocal fymptoms of chearfulnefs and alacrity of mind. 

 Thus the expreflions of pleafure and pain by brute animals, 

 though not uttered in the precife manner with thofe of the 

 human fpecies, are perfe£lly analogous, and anfwer the fame 

 intentions of Nature. 



By refpiration, and the inflruments employed in the per- 

 formance of it, the larger animals are not only brought forth, 

 but are enabled to extract milk from the breads of the 

 mother. By refpiration, odors are conveyed to the ncfe j 

 coughing, fneezing, yawning, fighing, naging, vomiting, and 

 many other functions in the animal oeconomy, are at leaft 

 partly accompiiflied. 



After this general view of the refpiration of man and of 

 quadrupeds, we proceed, according to the method laid down, 

 to give fome account of the fame function in the other cialles 

 of animals. 



With regard to birds, though, hke other land-animals, 

 they refpire by means of lungs, Nature has enabled them to 

 tranfmit air to almoft every part of their bodies. The lung^ 

 of birds are fo firmJy attached to the diaphragm, the ribs, 

 the lides, and the vertebrae, that they can admit of very lit- 

 tle dilatation or contraction. Inftead of being impervious, 

 the fubftance of the lungs, as well as of the diaphragm, to 

 which they adhere, is perforated with many holes or pafTag- 



