18 THE 1'LA.NT. 



carbonic acid. Tlie same occurs when bodies cou- 

 taining carbon decay^ as this is simply a slower 

 burning and produces the same results. In the 

 breathing of animals the carbon of the blood com- 

 bines with tlie oxygen of the air drawn into the 

 lungs, and their breath, when thrown out, always 

 contains carbonic acid. From this wo see that the 

 reproduction of this gas is the direct effect of the de- 

 struction of all organized bodies, whether by fire, 

 decay, or consumption by animals. 



Furnaces are its M'holesale manufactories. Every 

 cottage fire is continually producing a new supply, 

 and the blue smoke issuing from the cottage-chim- 

 ney, contains materials for making food for the cot- 

 tager's tables and new faggots for his fire. The 

 M'ick of every burning lamp draws up the carbon 

 of the oil to be made into carbonic acid in the 

 flame. All matters in process of combustion, decay, 

 feimentation, or putrefaction, are returning to the 

 atmosphere those constituents, which they obtained 

 from it. Every living animal, even to the smallest 

 insect, by resjDiration, spends its life in the produc- 

 tion of this material, so necessary to the growth of 

 plants, and at death gives up its body in part for 

 such formation by decay. 



Thus we see that there is a continual change from 

 the carbon of plants to air, and from air back to 

 j)lants, or through them to animals. As each dollar 

 in gold that is received into a country permanently 

 increases its amount of circulating medium, and each 

 dollar sent out p'unnanently decreases it until re- 



