BODY OF THE HOUSE. 53 



called a vertebra. The plural of vertebra is 

 vertebra. 



The seven lower vertebrae are very large 

 and strong. These parts of the frame are the 

 only supporters of the first or lower story. 

 The twelve next above them, belonging to the 

 second story, are somewhat smaller. The 

 seven which belong to the neck are smaller 

 still. Their size, in general, decreases not 

 suddenly, but gradually from the bottom up- 

 wards. They are placed one above another, 

 somewhat like tea-cups or saucers inverted and 

 piled up. 



The spine or back-bone is not only curious 

 in its shape and structure, but of the utmost 

 importance in the human frame. It has been 

 sometimes said, that " if one member," in any 

 part of the body, " suffer, all the members 

 suffer with it." This is especially true of the 

 spine. 



EACH VERTEBRA. Each vertebra has a 



hole of considerable size in the middle of it. 



See 6 in the engraving below. What I show 



you, is the upper surface of one of the verte- 



5* 



