488 DR GEORGE WILSON ON NEW PROCESSES FOR FLUORINE, &c. 
and mica slate, will acquire additional significance 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 succeed- 
ing papers. 

