3t> tXAMItfATtON OF THE TEETH. 



riments. t am inclined to afcribe it to the latter. The fim- 

 plicity of the doctrine of heat, maintained by Drs. Irvine and 

 Crawford, is to me fo ftrikingly apparent, when contrafled 

 with the now prevailing, but, I think, unfounded diftin&ions 

 of combined and uncombined, or free caloric, that I fliould be 

 very unwilling to difcard it; but upon clear proof of its being 

 incompatible with the phenomena. 



I am your obliged friend, 



J. D ALT ON". 



The bones long 

 ago analy fed j 



bat not the 



euimel of the 

 teeth. 



Tlii* Uft is the 

 author** objeft. 



, VIII. 



Memoir containing the Phi/fical and Chemical Examination of 

 the Teeth. By Cit. Josses, of Remits *. 



jT\.MONG thofe animal matters which have been analyfed 

 with the mod attention, the bones may be felecled. For a 

 long time, they were believed to be formed of earthy fnb- 

 ftances, the particles of which were connected by a peculiar 

 gluten : at prefent it is afcerlained, that they are a true faline 

 concretion, known by the name of phofphate of lime, mixed 

 with a certain quantity of gelatine. The experiments made 

 to prove this have been fo often repeated, particularly in the 

 extraction of phofphorus, and are fo well known, that they 

 cannot now be called in queftion. 



But though there be no longer any doubt as to the ofleous 

 fubflance, the fame cannot be faid of the covering which 

 cloaths the furface of the expofed part of the teeth. This 

 Covering, conftantly confounded in the general clafs of J>ones, 

 feems never to have undergone a thorough examination, alone, 

 by an accurate decompotition. All the authors who have 

 treated of this fubjecl, appearing to have done it too inatten- 

 tively, have committed errors, which it is effential to correct. 

 Though it has been fuppofed, that this covering was formed 

 of materfals analogous to the ofleous part, to which it adheres, 

 it is neverfhelefs true, that it differs from it etfentially, in its 

 phyfica! and chemical qualities, and that it poflefles peculiar 

 properties, as may be eafily (hewn. 



The intention of this work is, therefore, to afcertain the 

 corapofltion of this covering, to (hew its phyiical and che- 



# Annales de Chemie, xliii. 2. 



mical 



