142 DESCRIPTION OF THE SKELETON. 



the same way as to a person riding in a carriage, the 

 Jolt of the wheel passing over a stone, is diminished 

 by being diffused over the whole vehicle, in conse- 

 quence of the elasticity of the springs. The safety 

 imparted by this arrangement to the delicate and 

 important vital organs is apt to be lost sight of, from 

 the very smoothness with which it enables us to 

 move along ; but it will be perceived if we reflect on 

 ; the shock given to the whole system by taking a 

 single false step in going up or down a stair. The 

 parts have then no time to adapt themselves to the 

 exigencies of the moment, and to put the proper 

 springs in play for the equal distribution of the im- 

 petus. Death has been occasioned by accidents of 

 this kind. 



The fabric resulting from the connexion of all 

 these pieces in their natural order of arrangement 

 is called the Skeleton. When the connexion is 

 maintained by means of the ligaments which bound 

 the pieces together during life, the whole is called 

 a natural skeleton ; but if the place of the ligaments 

 be supplied by wires, the skeleton is then said to be 

 artificial. The bones entering into the composition 

 of the human skeleton exceed 200 in number. Each 

 is separate from, but intimately connected with, the 

 rest ; and of a shape, size, and construction in ex* 

 act harmony with the kind and extent of motion 

 which it is destined to exercise. Dry and uninviting 

 as such a subject may seem at first sight, there are 

 found, nevertheless, on closer examination, many 

 points of inquiry both interesting and instructive, to 

 which I shall briefly advert. 



The three great divisions of the skeleton recog- 

 nised by anatomists are, the head, trunk, and extrem- 

 ities. The first is well known ; the second includes 

 the two great cavities, the thorax or chest, and the 

 abdomen or belly ; and the third comprises the arms 

 and legs, or upper and lower extremities. 



Each of these presents a structure beautifully 



