35G Dr George Wilson on the Presence of Fluorine 



lepidolite, and most of the other compound fluorides, with 

 granite, gneiss, and mica slate, will acquire additional signifi- 

 cance from the discovery that fluorine occurs in the rocks 

 which form their matrices. 



4th, The presence of fluorine in plants is now rendered 

 doubly probable, as it may enter them alike in combination 

 with a metal such as potassium, sodium, or calcium, or in 

 association with silica. 



5th, The presence of fluorine in animals may now be fully 

 accounted for ; as it not only enters their bodies in the water 

 they drink, but is contained in the vegetable food, by which, 

 directly or indirectly, the whole animal kingdom is sustained. 

 The prosecution of these views, however, will be taken up in 

 succeeding papers. 



— — i — i 



On the Presence of Fluorine in the Stems of Graminece, Equi- 

 setacece, and other Plants ; with some Observations on the 

 Sources front which Vegetables derive this element. -By 

 George Wilson, M.D.* 



Table of Plants examined for Fluorine. The numbers represent 

 grains of ashes, except in the ease of Tabasheer and Wood Opal. 

 The blanks imply that the weight was not known. 



. L .' Name of Plant, 



in brains. 



200 Horsetail (Equisetum liraosum), . . Distinct etching. 



Common bamboo (Bambusa arundinacea), 



Charcoal (derived chiefly from oak, and to a 



smaller extent from birch), 



Coal, 



Barley straw, .... 



Hay (Ryegrass), 



35 Equisetum variegatum, .... Faint etching. 



19 hyemale, 



255 palustre, 



Tussac grass (Dactylis caespitosa), 



99 Elymus arenarius, 



495 Sugar cane (Saccharum officinarum), 



1040 African teak, .... 



Smilax lati folia, No etching. 



Common rosemary (Rosmarinus officinalis), . 



235 Nepaul bamboo (Bambusa Nepalensis), . . 



Common Fern (Polypodium vulgare), 



, — _ — , 1 



* Head to the Botanical Society of Edinburgh, July 1852. 



