BODY OF THE HOUSE. 63 



mits of one sort of motion, viz., forward and 

 backward, like a door on its hinges. But the 

 connection of the radius, or smaller bone of the 

 arm, with the ulna, or larger one, is such that 

 it more than makes up for this deficiency. 

 Then the wrist, consisting, as it does, of eight 

 bones, all movable, and being so connected 

 with the lower bones of the arm as to admit of 

 very free motion, renders the arm one of the 

 most useful contrivances in the world. It will 

 perform as various and as rapid movements as 

 the trunk of the elephant ; and would proba- 

 bly, if it were not so common, excite as much 

 surprise. 



It was said that this whole member could be 

 torn off without spoiling the building. Ches- 

 elden, an English anatomist, relates that a mil- 

 ler had the whole arm, shoulder-blade and all, 

 torn off, and yet recovered. The great dan- 

 ger, in such cases, is from bleeding ; but torn 

 blood-vessels do not bleed so freely as cut ones. 



THE HAND. I wish to give you a few 

 particulars about the hand. This extremity of 

 the arm is by far the most curious part of it. 



