THr. HUMAN FRAME. 15 



mation and satisfaction, by even examining the bones of the 

 animals which come upon his table. Let him take, for exam- 

 ple, into his hands a piece of the clean-picked bone of a hare's 

 back, consisting, we will suppose, of three vertebrae. He will 

 find the middle bone of the three so implicated, by means of its 

 projections or processes, with the bone on each side of it, that 

 no pressure which he can use will force it out of its place 

 between them. It will give way neither forward nor back- 

 ward, nor on either side. In whichever direction he pushes, 

 he perceives, in the form, or junction, or overlapping of the 

 bones, an impediment opposed to his attempt, a check and 

 guard against dislocation. In one part of the spine he will 

 find a still further fortifying expedient, in the mode accord- 

 ing to which the ribs are articulated to the spine. Each 

 rib rests upon two vertebrae. That is the thing to be re- 

 marked, and any one may remark it in carving a neck of 

 mutton. The manner of it is this : the end of the rib is di- 

 vided by a middle ridge into two surfaces, which surfaces 

 are joined to the bodies of two contiguous vertebrae, the 

 ridge applying itself to the intervening cartilage. Now this 

 is the very contrivance which is employed in the famous iron 

 bridge at my door at Bishop-Wearmouth, and for the same 

 purpose of stability, namely, the cheeks of the bars which 

 pass between the arches ride across the joints by which the 

 pieces composing each arch are united. Each cross-bar rests 

 upon two of these pieces at their place of junction, and by 

 that position resists, at least in one direction, any tendency 

 in either piece to slip out of its place. Thus perfectly, by 

 one means or the other, is the danger of slipping laterally, or 

 of being drawn aside out of the line of the back, provided 

 against ; and to withstand the bones being pulled asunder 

 longitudinally, or in the direction of that line, a strong mem- 

 brane runs from one end of the chain to the other, sufficient 

 to resist any force which is likely to act in the direction of 

 the back or parallel to it, and consequently to secure the 

 whole combination in their places. The general result is. 



