NATURAL THEOLOGY. 109 



each edge, equidistant on each side from the mid- 

 dle hne of the back. When the vertebrae are put 

 together, these notches, exactly fitting, form small 

 holes, through which the nerves at each articula- 

 tion issue out in pairs, in order to send their bran- 

 ches to every part of the body, and with an equal 

 bounty to both sides of the body. The fourth 

 purpose assigned to the same instrument is the 

 insertion of the bases of the muscles, and the sup- 

 port of the ends of the ribs ; and for this fourth 

 purpose, especially the former part of it, a figure 

 specifically suited to the design, and unnecessary 

 for the other purposes, is given to the constituent 

 bones. Whilst they are plain, and round, and 

 smooth towards the front, where any roughness or 

 projection might have wounded the adjacent vis- 

 cera, they run out behind, and on each side, into 

 long processes, to which processes the muscles 

 necessary to the motions of the trunk are fixed, 

 and fixed with such art, that, whilst the vertebra 

 supply a basis for the muscles, the muscles help 

 to keep these bones in their position, or by their 

 tendons to tie them together. That most impor- 

 tant, however, and general property, viz., the 

 strength of the compages, and the security against 

 luxation, was to be still more specially consulted ; 

 for, where so many joints were concerned, and 

 where, in every one, derangement would have 

 been fatal, it became a subject of studious precau- 

 tion. For this purpose the vertebras are articulat- 

 ed, ihat is, the movable joints between them are 



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