TEETH. 



What is marked sand was in the hippopotamus enamel grains of 

 sand lodged mechanically. In human teeth it was silica, tinged 

 slightly with iron. 



The following table exhibits the constituents which I ex- 

 tracted from the ivory of various specimens of teeth subjected to 

 analysis : 



Human 

 Hippotaraus. Walrus. adult tooth. 



Cartilage, , . 28-87 .32-11 25-38 



Subsesquiphosphate of lime, 48-30 51-93 54-14 



Carbonate of lime, . 7-90 2-58 5-76 



Magnesia, . . 1-03 0-94 1-37 



Chloride of potassium, . 0-30 ... \ 



Chloride of sodium, . . . . . 3-30 J 



Silica, . . ... 0-21 0-33 



Moisture, . 13-09 10-33 10-37 



99-49 101-40 100-37 



A carious human tooth, having a specific gravity of 1-533, 

 being subjected to analysis, yielded, 



Cartilage, . 57-78 



Subsesquiphosphate of lime, 30-00 

 Carbonate of lime, . 2-09 

 Magnesia with trace of silica 



and peroxide of iron, 2*05 

 Chloride of potassium, 1-25 



Moisture, . 9-45 



102-62 



The crusta petrosa from an elephant's tooth, having a specific 

 gravity of 1-892, being analyzed, yielded the following constitu- 

 ents : 



but contained a good deal of ivory. The animal membrane was at least partly 

 cartilage. The deficiency was occasioned by a portion of the cartilage having 

 been dissolved in the muriatic acid. The specimen examined was in powder. 

 It was impossible to determine whether it was pure enamel by the eye. 



