TEETH. 413 



[Callus has been analysed by Lassaigne and Von Bibra. 

 Lassaigne examined the outer and inner portions of a mass 

 of callus. He found : 



External portion. Internal portion . 



Phosphate of lime . . .33-3 32-5 



Carbonate of lime . . . 5-7 6-2 



Soluble salts . . . 11-3 12-8 



Animal matter . . . 50-0 48-5 



The following analyses were made by Von Bibra : 



Callus from the Callus from the 



tibia of a hare. rib of a horse. 



Phosphate of lime with fluoride ofi 



Y 32-62 43-90 



calcium . . ./ 



Carbonate of lime . . 1-01 5-69 



Phosphate of magnesia . . 1-13 1-20 



Salts . . . 1-79 0-74 



Cartilage . . . 61-41 46-97 



Fat ... 2-04 1-50 



Hence callus does not contain so large an amount of earthy 

 salts as true bone.] 



The Teeth. 



The teeth, like the bones, consist of phosphate and carbonate 

 of lime, fluoride of calcium and cartilage. The bony matter of 

 the tooth is covered superiorly with enamel, while the fangs 

 are coated with cement or cortical matter, which likewise over- 

 lays the enamel of the crown. Of the three constituents of 

 tooth, enamel, bone (dentine), and cortical substance, the last 

 is the poorest in inorganic matter. Lassaigne found therein : 



Organic matter . . . 42-18 



Phosphate of lime . . . 53-84 



Carbonate of lime . . . 3'98 



The osseous portion (dentine) hardly differs from true bone. 

 Berzelius found therein : 



Cartilage and vessels . . . 28-0 



Phosphate of lime with fluoride of calcium . 64-3 



Carbonate of lime . . .5-3 



Phosphate of magnesia . . .1-0 



Soda, with chloride of sodium . .1-1 



