82 DEPARTMENT OF AGRICULTURE GEORGIA. [368] 



thus illustrating the beautiful harmony and economy of 

 natural laws. 



Carbonic acid is essential to the life and growth of plants, 

 oxygen to the respiration and life of animals. They re- 

 ciprocally supply each other's wants. Plant life is, how- 

 ever, independent of animal, since all of the carbonic acid 

 contained in vegetation consumed by animals, would, in 

 the natural process of decay, be returned to the air with- 

 out the intervention of animals, which only expedite its 

 return ; but animal existence is absolutely dependent upon 

 vegetation. 



Animals consume, either directly or indirectly, only what 

 plants produce. They produce but little directly from the 

 mineral world. 



Graminivorous animals feed upon vegetation only, to 

 supply food for carnivora, so that [it is almost literally 

 true that "all flesh is grass." 



There is another reciprocal relation between the atmos- 

 phere and vegetation, which is of great practical import- 

 ance, and which man may to some extent control. 



This is found in the mutual influence of vegetation and 

 the moisture of the atmosphere upon each other. 



Plants, by evaporation from their leaves, restore a vast 

 amount of moisture to the atmosphere, and thus materi- 

 ally meliorate its condition. 



"A recent experimant made by Knop, showed that a 

 dwarf bean exhalted, in 23 days in September and Octo- 

 ber, 13 times its weight of water. He further established 

 the fact, that a grass plant will exhale its own weight of 

 water in 24 hours in the hot, dry days of summer; and that a 

 maize plant exhaled 36 times its own weight of water 

 from May 2d, to September 4th." [Scientific Agricul- 

 ture. PENDLETON. ] 



From these facts, some idea may be formed of the vast 

 amount of moisture which js exhaled in the aggregate, 

 by the whole vegetation of the globe. It demonstrates also 



