1 10 THE HOUSE I LIVE IN. 



The shells of many of the testaceous and 

 crustaceous animals, are of very great value. 

 Such are the tortoise shell, the pearl, &c. 



The shell of the tortoise, in particular, is 

 exceedingly valuable in the arts. You will 

 observe that these shells to animals, not only 

 serve as a support to their softer parts, but also 

 as a defence. What would become of the 

 tender frame of the poor tortoise, lobster, crab, 

 and oyster, if they were not covered over, as 

 with a shield, by a hard buckler of shell? The 

 soft parts of the human body are, in many 

 instances, well defended by the solid frame on 

 the outside of them, in the same manner. 

 Such are the brain, the spinal marrow, the 

 lungs, the heart, and the liver. 



Now one principal part of all the shells of 

 animals is lime. So that there is not so much 

 difference between the bones of man and the 

 shell of the tortoise or the lobster, as you may 

 have supposed, though the color is somewhat 

 different. A very large proportion of the 

 lobster shell is lime ; in the tortoise shell the 

 proportion is small. Horn has but a very little 

 lime in it. 



