OF NATURAL HISTORY. 117 



Befide the circulation of the blood, and the continuation 

 of the vital warmth, refpiration gives rife to many other im- 

 portant fuaftions in the animal oeconomy. All animals who 

 rcfJ3ire, beiide a watery vapor, exhale great quantities of me- 

 phytic or corrupted effluvia, which, if retained in the lungs, 

 or breathed by other animals, would foon prove fatal. The 

 mufcles of refpiration, of which we have the command, are 

 employed in many other operations of the body, beiide the 

 mere a6l of breathinf^ air. All animals furnillied with lunps 



O (J 



exprefs their wants, their affections and averfions, their 

 .pleafures and pains, either by words, or by founds, peculiar 

 to each fpecies. Thefe different founds are produced by 

 ffraitening or widening the glottis and wind -pipe, or, in 

 general, the paffage through which the air paffes in refpira- 

 tion. The inferior animals are by this means enabled to ex- 

 prefs themfelves, though not by articulate founds, in fuch a 

 manner as to be perfectly intelligible to every individual of 

 a fpecies. On man alone. Nature has beflowed the faculty 

 of fpeaking, or of expreffing his various feelings and ideas, 

 by a regular, exteniive, and eftablifhed combination of arti- 

 culate founds. To have extended this faculty to the brate 

 creation, would not, it is probable, have been of any ufe co 

 them ; for, though fome animals can be taught to articulate, 

 yetj from a defect in their intellect, none of them Icem to 

 have any idea of the proper meaning of the words they utter. 

 Speech is performed by a very various and complicated ma- 

 chinery. In fpeaking, the tongue, the lips, the jaws, the 

 whole palate, the nofe, the throat, together with the muf- 

 cles, bones, &c. of which thefe organs are compofed, are all 

 employed. This combination of organs we are taught to 

 ufe when fo young that we are hardly confcioKs of the la- 

 borious talk, and far lefs of the manner by which we pro- 

 nounce different letters and words. The mode of pronounc- 

 ing letters and words, however, may be learned by attentive- 



