Mr. Bell on the nerves which associate the muscles , &c. 28 5 
into which it will be necessary to enter, that already prac- 
tical benefits have arisen from the former paper ; that the 
views presented there, as connected with general science, 
being carried into practice, have enabled the physician to 
make more accurate distinctions of disease, and the surgeon, 
in removing deformity, to avoid producing distortion. 
Of the motions of the thorax , as affording a key to the intricacy 
of its nerves. 
We have seen the necessity of considering all the func- 
tions and relations of a part of the animal machine, the nerves 
of which we propose to distinguish according to their uses ; 
and this is even more necessary with respect to the thorax 
than the face. This will be evident, if we make a mere cata» 
logue of the uses of this compages of bones and muscles. 
Besides affording support and protection to the heart and 
lungs, and the viscera of the higher region of the abdomen, 
the thorax performs these offices : 
1. It alternately opposes and yields to the weight of the 
atmosphere, thus producing respiration. 
2. In addition to the uniform motion of the chest in breath- 
ing, there is the occasional increase and agitation commen- 
surate to the excited state of the animal frame, when ad- 
ditional muscles are brought into action. 
3. There is the exertion of the respiratory apparatus in 
natural voice, and in articulate language. 
4. Through the nerves and muscles employed in respi- 
ration, are also exhibited the emotions and passions of the 
mind. 
