CRUSTS. 261 



One hundred parts of cray fish crust contain 



Carbonate of lime, . 60 



Phosphate of lime, . .12 



Cartilage, . . 28 



100* 



John analyzed the shield or shell of the fresh water crab in 

 181 If and extracted from it the following constituents, 

 Cartilage, . . .33-3 



Carbonate of lime, including a little common salt, ) 

 iron, manganese, and colouring matter, j 



Phosphate of lime, . . . 5 *7 



100-0 



Lobster's claws were subjected to analysis by M. Pagurus in 

 1823. He obtained 



Animal matter, . 17*18 



Carbonate of lime, . 68-36 



Phosphate of lime, . 14-06 



99-60J 

 The shell of the lobster gave him 



Animal matter, . . 28-6 



Soda salts, . . 1-6 



Carbonate of lime, . 62-8 



Phosphate of lime, . 6-0 



Phosphate of magnesia . 1-0 



100-0 

 One hundred parts of hen's egg-shells contain 



Carbonate of lime, . 89-6 



Phosphate of lime, . 57 



Animal matter, . 4 '7 



100.0 



* Merat-Guillot, Ann. de China, xxxiv. 71. 



f Chemische Untersuchungen, ii. 49. 



J: Schweigger's Jour, xxxix. 440. 



Vauquelin, Ann, de Chim. xxix. 6. 



