238 Dr Maclagan on Gutla Percha. 



mineral kingdom, fluorine is a very common attendant upon 

 the phosphates, as, for instance, in the Apatites, Wagnerite, 

 Wavellite, Urinite, &c. ; and, I think, if we search the mineral 

 kingdom, we shall not find so constant an association of any 

 two elements as fluorine and phosphorus. All the phosphates 

 of the alkalies and earths contain fluorine. 



If, then, this element is associated with the phosphates, 

 they must exist together in the soils, arising from the dis- 

 integration of the rocks containing those minerals, and the 

 plants growing upon those soils would, upon taking up the 

 phosphates, naturally appropriate the accompanying fluo- 

 rides ; which two classes of salts would subsequently pass to 

 the same portion of the animal feeding upon those plants, 

 namely, to the bones. 



The reason why the existence of fluorine in recent bones 

 is doubtful, may be owing to the fact, that the great mass of 

 the phosphate of lime originally in the soil has, from various 

 causes, disappeared, and with it the fluoride of calcium ; and 

 that the portion of this latter still remaining is so small, 

 that, notwithstanding the double condensation that it under- 

 goes, through the agency of plants and animals, it is not in 

 suflicient quantity to come readily within the reach of our 

 tests. — Americati Journal of Science and Arts, vol. xlviii.. 

 No. 1, p. 19. 



0/i " Gutta Percha" a peculiar variety of Caoutchouc. By 

 Douglas Maclagan, M.D., F.R.S.E., &c. Communi- 

 cated by the Royal Scottish Society of Arts.* 



Gutta Percha is the Malayan name for a substance which 

 is the concrete juice of a large forest tree, native of the 

 shores of the Straits of Malacca, Borneo, and the adjacent 

 countries. The tree yielding it is unknown botanically, all 

 the information we possess regarding it being, that it is a 

 large forest tree, and yields this product abundantly. We 

 are indebted for our knowledge of it to Dr W. Montgomerie, 



* Read before the Society 23d June 1845. 



