216 NATURAL THEOLOGY. 



from the surface of the brain, still more effectually 

 protects it. 



A person tumbling sideways pitches on the 

 shoulder, and the convexity of the head comes to 

 the ground precisely on that point (the centre of 

 the parietal bone) where the bone is thickest and 

 most dense. 



It is, on the whole, impossible to study the 

 forms of the head without acknowledging that the 

 shape, thickness, and texture of the skull have 

 reference to the liability to pressure and blows 

 from without. 



To take a further example : — It seems very 

 natural, in carrying a burden, to poise it on the 

 head. Now, whether we take the carpentry (called 

 a centering) on which the stones of the arch of a 

 bridge are laid in building it, or the arch of stone, 

 or a dome — (for with all these the bones of the 

 head may be aptly compared) — there has been 



The figure represents the two parietal bones — forming an arch, 

 or a surmounted dome. 



