NATURAL THEOLOGY. 103 



T. This is stating the case a little too strongly, 

 though I am sensible of an admirable author you 

 may have so understood. It was not, I presume, his 

 intention to suggest, there could have been no en- 

 largement and contraction of the chest, if the ribs, 

 in their natural position, had passed directly around 

 the body. But then this is certain, the motion in 

 this case, must have been very considerable in the 

 ribs to have produced any effect ; whereas a slight 

 rising from a sloping position changes the cavity of 

 the chest immediately. 



B. This is very plain. We can see it exempli- 

 fied by placing our hands against our sides with the 

 fingers touching in front, so as to resemble ribs. If 

 they pass directly across, a slight motion does not 

 change their distance from the breast ; and if they 

 were the real ribs, this motion would not effect any 

 change in the capacity of the chest : but, if we first 

 slope them downwards, we find a trivial rising ex- 

 tends them instantly from the body. 



T. There is other mechanism beside the ribs con- 

 cerned in the action of breathing or respiration ; espe- 

 cially the rising and falling of the diaphragm, which 

 is a muscle that separates the chest from the cavity 

 beneath. And the wisdom of this is the more observa- 

 ble, as the ribs are liable to lose their elasticity by 

 age, and sometimes become incapable of motion. 



THE LOWER LIMBS. 



The limbs, ivhich carry and support the body, 

 form another remarkable part of our structure. 



