THE FOOD OF PLANTS. 277 



The wonderful substance (formerly so rare and 

 costly), phosphorus, is so essential an ingredient 

 in the food of plants, that not one of any kind can 

 flourish without it. This highly combustible body, 

 so offensive to taste and smell, and withal so poi- 

 sonous, enters the plant in combination with oxygen, 

 with which it forms phosphoric acid. The entire 

 supply o phosphorus employed in the arts comes 

 from plants, and they hunt it. from the soil atom 

 by atom,*and incorporate it into their structures. 

 Animals feeding upon plants abstract the element, 

 and it takes its place in the bones in combination 

 with lime, forming basic phosphate of lime. We 

 gather the bones of the dead animals, and after 

 calcination, subject them to chemical treatment, 

 and thus isolate the phosphorus in a pure state in 

 large quantities. How curious is this cycle of 

 changes and transformations ! We can in no way 

 obtain a clearer conception of them, than by re- 

 flecting \ upon the fact that the phosphorus found 

 upon the end of every friction match we use in our 

 dwellings has been gathered from the soil by veg- 

 etables, and passing through their organization, 

 it has taken its place in the bones of oxen, cows, 

 or horses, and from thence passed into the labora- 

 tory of the chemist, where it is fitted to subserve 

 the most useful purposes. If this substance had 

 a tongue, what an interesting history of adventures 

 it could unfold J 



