Of the formation of the Teeth in feveral animals ; the flruclure of the 

 human Teeth explained, and fame of the diforders to which the fame are 

 liable accounted for. 



XJlAVING taken great pains to invefligate the formation of the 

 elephant's tooth, and exanihied into the nature of it by every means 

 I could devife, I found it to confift only of a collection of tubuli, or 

 pipes, which are exceedingly fmall, and all derive their origin from' 

 the inner part of the tooth, for I never could difcover any of them 

 lying longitudinally or lengthwife in it. 



Upon examining that part of the tooth where the honey fubftance 

 is but thin, which is where it is united to the head, I very- plainly 

 perceived that one end of thefe tubuli took its rife from the cavity 

 "within, and the other end extended to the circumference, which cir- 

 cumference or outfide was compofed of a kind of fcaly particles laid 

 one on another, and I confidered with myfelf whether each feries or 

 layer of thefe fcaly particles might not be the fubftance or tliicknefs 

 formed in the fpace of one year. 



Purfuing thefe my obfervations in the examination of that part of 

 the tooth where to the eye it feems perfe6lly folid, I there found it 

 to have, near the middle, a fmall cavity, through which cavity I con- 

 cluded the nutritive fubftance muft be conveyed, for the continual 

 fupport and increafe of the tooth. And upon examining the tubuli 

 round about this fmall cavity, I perceived that they all arofe from 

 thence, and fpread themfelves all round towards the circumference. 

 I endeavoured to examine ftill farther, beyond the part where this 

 eavity ended, in order to difcover whether from thefe firft formed 



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