CHAPTEE VII. 



THE ATMOSPHEEE AND VEGETATION. 



LET us now proceed to make inquiry as to 

 the mutual relations subsisting between the 

 air and the luxuriant vegetation which sur- 

 rounds us. How and in what way are these 

 blades of grass affected by the summer breath- 

 ings which pass in wave-like movements over 

 them ? The direct connexion of animals with 

 the chemistry of the atmosphere can, as a 

 general rule, only be said properly to be imme- 

 diately established when they first draw the 

 breath of life, although undoubtedly they are 

 indirectly the recipients of its beneficial in- 

 fluences in their previous condition of imma- 

 turity. In birds, however, and oviparous 

 creatures generally, from the earliest dawn 

 of the principle of life within the shell, this 

 relation commences, only to cease with their 

 death. The presence of the atmosphere is in 

 like manner essential to the commencement 

 of vegetative life. The seed can only begin 

 to grow, or, in other words, to germinate, by 



2 A 



