30 FORM AND ACTION. 



a conical figure : small and contracted in front ; broad, deep, and 

 capacious in the middle and posterior regions. 



The connexion between the ribs and the bones of the spine 

 is by means of small joints which admit of a limited hinge-like 

 motion between them ; but to the breast-bone the ribs are attached 

 by distinct cartilages — long pieces of gristle, so formed as to appear 

 like a continuation of the ribs themselves, and virtually, indeed, 

 to answer in some respects a like purpose ; for they complete the 

 inclosure inferiorly, and to the contained parts offer, to the extent 

 they reach, as effectual protection as the ribs would give. But 

 they serve purposes bones could not answer. They enable the 

 ribs to enjoy that motion, outwardly, which their joints with the 

 vertebrae intended they should have, for the purposes of respira- 

 tion ; they also enable the ribs to accommodate themselves, by 

 partial turns, twists, and inclinations, to the various movements of 

 the animal : further, by their own elasticity, they endow the ribs 

 with that power of yielding, that high degree of resiliency, which 

 proves the means of their resisting fracture in hundreds of instances 

 where, without the cartilages, fracture must have ensued. The 

 blows, the pressure, the squeezes, the hard rubs, the ribs get, 

 would over and over again break them to shatters were it not for 

 their cartilages. How rarely do we hear of a horse getting his 

 ribs broken, even from the heaviest falls, from the hardest blows, 

 from the greatest weight imposed upon them ! — when any shock of 

 this description is given, we hear a sudden burst of air from the 

 chest, occasioning momentary exhaustion ; but we rarely indeed 

 find it productive of fracture of the ribs. Far other and fatal must 

 have been the consequences had the entire rib been one solid 

 piece of bone : to say nothing about the difficulty any act of exer- 

 tion must necessarily have occasioned in the breathing, any violent 

 blow or fall, or great weight jolted upon the back, must have 

 broken the ribs into pieces. On the other hand, had the ribs been 

 composed from end to end of cartilage solely, the form of the arch 

 could not have been sustained ; neither could the effects of blows, 

 or superimposed weight have been resisted ; but, sooner or later, 

 the arches must have become bent inwards, and so encroached 

 upon the cavity of the chest as to have compressed the organs of 

 respiration and circulation to that degree that could not but have 



