42 EXAMINATION OF THE TEETH. 



canted and filtered, and then poured upon a new quantity of 

 powdered enamel, and I proceeded as before : at the end of 

 a fecond digeftion of twenty-four hours, its tafte did not ap- 

 pear to be any longer alcaline. 

 Examination of Following the directions of the fame authors, I examined 

 luSon^tnorder the carbonate °f P *^ »* which I had digefted the enamel, 

 to detect oxalic with acetite of lead and barytes ; and obtained a very abun- 



fuccef 5 Vith0Ut dant white P reci P itate - Thefe refults, fimilar to thofe ob^ 

 tained by the above two chemiffc, from mural or oxalite calr 

 culi, or calculi of oxalate, gave reafon to fuppofe that the 

 oxalic acid being combined with the lime in the enamel of 

 the teeth, formed there, alfo, an oxalate of lime. To afcer* 

 tain this, I tried to decompofe the two precipitates I have 

 mentioned, but all my endeavours on this point were without 

 fuccefs *. 

 Enamel feparat- Fearing that the fulphuric acid, which I had ufed in my 

 tefter. ° *~ preparatory procefTes, had altered fome of the component 

 parts of the enamel of the teeth, I procured fome by another 

 method, and recommenced my operations. Papin's digefter 

 juflified my hopes ; it afforded me an eafy method of obtain- 

 ing an abundant quantity, completely difengaged from the 

 offeous part, and which had not experienced any change from 

 an acid. The enamel obtained by this new method, and fub- 

 mitted to the fame experiments, no longer yielded fimilar refults. 



* If my fufpicions had been realifcd, it will be perceived, that 

 the oxalate of lime being thus difcovered completely formed by 

 nature in living animals, and neceflary in the organifation of the 

 teeth, the oxalic acid would become a ftriking part of the beau- 

 tiful theory of the two learned men whom I have cited. This 

 would have afforded a natural explanation of the calculous oxalates 

 fn the urinary concretions, as well as of the oxalic acid ibmetimes 

 obferved in humours, though, their phenomena are always thought 

 to be unufual, and to arife from morbific affeiiiorjs. 



As the formation of the enamel takes place in the firft years of 

 life, and neceflarily ceafes after the laft dentition, it may eafily be 

 conceived, that the reflux of the oxalic acid, or the liquid oxalate 

 lime, by way of urine, which has fo many points of ref'emblance 

 to offeous fubftances, muft have given rife to the concretion of the 

 mural calculi, which are more common in youth than in age, as 

 Fourcroy has well obferved in his works. But after much labour, 

 I found myfelf compelled to abandon my firft expectations, and to 

 endeavour, by new inveftigation*, to diicoverlUe truth. 



This 



