£XAMIL OF TEETH. 215 



tluoric acid united to lime in the enamel of human teelh. The ~^n«5 '^aid by 

 extraordinary refults of thefe relearches, induced me to repeal cxiftin the en- 

 them; but before I mention the experiments from which I amel of teeth. 

 have drawn conclufions different from Ihofe of the above- 

 mentioned chemift, it may perhaps be proper to quote that 

 part of Gay-Luflac's letter which relates to the prefent fub- 

 jecl: 



*' M. Morichini having detached fome of the enamel from Quotation to 

 human teeth, (uppofed that it might bear fome refemblance in '''^^ e^t^l. 

 its compolilion to the enamel of (he foflil teeth of an elephant, 

 in which, on a former occafion, he had detached fluoric acid; 

 he therefore fubjected it lo analyfis, and perceived, to his 

 great fatisfadlion, that it contained a large proportion of fluo- 

 ric acid. 



To render thefe experiments more conclufive, he fubmif- Morichini fays 

 ted portions of the two fpecies of enamel, viz. that of the ^^'^^ ^*^^ ^"^"'^' 

 fofllil, and human teeth, and likewife fiuat of lime, to the aftbrdcd fluonc 

 adion of fulphuric acid, and found that the laQ of thefe three ^'"^ as well a» 

 fubftances yielded fluoric acid in the greateft abundance, and ^^^^^ . 

 (hat the enamel of foflil teelh yielded fomewhat more than 

 that of human teelh; but Morichini remarks, that thi> dif- 

 ference is merely owing tolhe prefence of animal matter in the 

 two kinds of enamel, and that the difengagemeni of the acid 

 from the fiuat may be retarded, by adding a htt!e gelatine to 

 that fubftance, after it has been calcined, and then drying the 

 compound. He moreover obferves that the vapours which and that tlic 

 fulphuric acid difengaged from any of thefe three fubftances, '^"'P''"''''^ "'"* 

 had the property of acting on glafs, of dcpotliing a liliceous pours that cor- 

 film on water, and other properties, which it is fcarcely ne- '^'•''^^ S'*'=*> &*^« 

 ceflary to mention. 



According to Morichini's experiments, one hundred parts Component parts 

 of the enamel of human teeth contain 30 parts of animal fub- °* c"^"!^' of" 



, ^ teeth according 



ftance, and 22 parts of fluat and pholphate of lime, with fbme to Morichini. 

 magnefia, alumine, and carbonic acid. He has not yet been 

 able to feparate the fluoric and phofporic acids from each other, 

 but thinks that the proportion of tlie latter muft be extremely 

 minute. M. Morichini has alio obferved that the enamel of 

 the foflTd teelh of the elephant differs from that of human teeth, 

 in containing a fmaller proportion of animal fubftance and 

 phofphoric acid ; but he thinks that the phofphoric acid which 

 he found in the enamel of human teeth tnay have been derived 



from 



