96 NATURAL THEOLOar. 



one moment and sing the next ; the respiration proceedmg 

 freely all the while. 



There is one case, however, of this double office, and 

 that of the earliest necessity, which the mouth alone could 

 not perform ; and that is, carrying on together the two 

 actions of sucking and breathing. Another route, therefore, 

 is opened for the air — namely, through the nose — which lets 

 the breath pass backward and forward, while the lips, in the 

 act of sucking, are necessarily shut close upon the body from 

 which the nutriment is drawn. This is a circumstance 

 which always appeared to me worthy of notice. The nose 

 would have been necessary, although it had not been the 

 organ of smelling. The making it the seat of a sense was 

 superadding a new use to a part already wanted — was 

 taking a wise advantage of an antecedent and a constitu- 

 tional necessity. 



But to return to that which is the proper subject of the 

 present section, the celerity and precision of muscular mo- 

 tion. These qualities may be particularly observed in the 

 execution of many species of instrumental music, in which 

 the changes produced by the hand of the musician are ex- 

 ceedingly rapid ; are exactly measured, even when most 

 minute ; and display, on the part of the muscles, an obedi- 

 'ince of action alike wonderful for its quickness and its cor- 

 rectness. 



Or let a person only observe his own hand while he is 

 writiJig ; the number of muscles which are brought to bear 

 upon the pen ; how the joint and adjusted operation of sev- 

 eral tendons is concerned in every stroke, yet that five hun- 

 dred such strokes are drawn in a minute. Not a letter can 

 be turned without more than one, or two, or three tendinous 

 contractions, definite both as to the choice of the tendon and 

 as to the space through which the contraction moves ; yet 

 how currently does the work proceed ; and when we look at 

 it, how faithful have the muscles been to their duty — how 

 true to the order which endeavor or habit has inculcated ! 



