220 



THE EEASOJS WHY. 



"Thus saith the Lord God unto these bones, Behold I will cause breath to enter 

 into you, and ye shall live : 



and complicated structure of the eyes, and supply points of 

 attachment, and grooves, by which the muscles are enabled to turn 

 the eyes freely, and thereby extend the field of vision. 



930. Why are the bones of the skull arched ? 



Because in that form they acquire greater strength, and hence 

 the utmost degree of safety is combined with extreme lightness of 

 material. 



Fig. 54. VIEW OP THE BONES OF THE THORAX, OB CHEST, SHOWING THE 

 PROTECTION AFFORDED TO THE ORGANS OF CIRCULATION AND BESPIHA- 

 TION. 



A. The sternum, or breast-bone. 



B B. The ribs, which rise a little from behind, and fall as they come for- 

 ward, by which they acquire a greater flexibility. 



C 0. The cartilaginous points of the short ribs, by which their expansive 

 and compressive powers are much increased. 



D E. Part of the vertebral column, or back-bone. 



931. Why are the bones of the skull divided by sutures 

 (seams), with, points which, fit into each, other like small teeth ? 



Because, by that arrangement, concussions of the skull, which 

 might be fatal to the brain, are deadened, and injuries from 

 accident greatly modified. 



