.'JO THE VITAL FUNCTIONS. 



receiving from the vegetable kingdom a large ac- 

 cession of oxygen, and is, at the same time, freed 

 from an equal portion of carbonic acid gas ; both 

 of which effects tend to its purification, and to its 

 continuing adapted to the respiration of animals. 

 Nearly the whole of the carbon accumulated by 

 vegetables is so much taken from the atmosphere, 

 which is the primary source from which they de- 

 rive that element. At the season of the year when 

 vegetation is most active, the days are longer than 

 the nights ; so that the diurnal process of purifica- 

 tion goes on for a greater number of hours than 

 the nocturnal process by which the air is vitiated. 

 The oxygen given out by plants, and the carbonic 

 acid resulting from animal respiration, and from 

 the various processes of combustion, which are 

 going on in every part of the world, are quickly 

 spread through the atmosphere, not only from the 

 tendency of all gases to uniform diffusion, but also 

 from the action of the winds, which are continu- 

 ally agitating the whole mass, and promoting the 

 thorough mingling of its different portions, so as to 

 render it perfectly homogeneous in every region of 

 the globe, and at every elevation above the surface. 

 Thus are the two great organized kingdoms of the 

 creation made to co-operate in the execution of the 

 same design : each ministering to the other, and 

 preserving that due balance in the constitution of 

 the atmosphere, which adapts it to the welfare and 

 activity of every order of beings, and which would 

 soon be destroyed, were the operations of any one 

 of them to be suspended. It is impossible to 

 contemplate so special an adjustment of opposite 

 ettects without admiring this beautiful dispensa- 



