HOW THK I'LANT LIVES 



V2: 



194rt. Air in which seeds have been germinating has suffered 

 a chanire; this can be shown in the following manner:— Fill a 

 larjje-mouthed bottle half full with soaked beans or peas, add a 

 small quantity of water, and cork it. After twenty-four hours, 

 pa«8 a lighted wax taper or waxed eord into the jar, and it will be 



extinguished. Make the same 

 tests in a jar of air, and see that 

 the taper burns. This is a striking 

 change. As a matter of fact, the 

 genniiiafion has increased the 

 amount of carbon dioxid and di- 

 minished the amount of oxygen, 



but other iiinro eliilionite experi- 

 ments would be needed to show 

 how we know that these are the 

 gases affected. 



19Ga. For a discussion of 

 the relation of wet soils to oxy- 

 gen-absorption, read Sorauer, 

 pp. 77-80. 



VJ6h. The "cypress 

 knees " which project 

 from the wafer in cypress 

 swamps in the South are 

 supposed to be aerating 

 organs. 



I97(i. If a plant is 

 burned in the air, the resulting ash is very small; but if burned 

 without free access of air, an in a charcoal pit, there remains 

 u charred mass almost aa great in volume as the substance 

 burned. This mans is largely carlton, a most imfiortant element 

 in all living matter, or protoplasm. In combination with the 

 elements of water, carl»on also forms most of the cellular tissue 

 of plants, likewise the starches and the nugam, all of which are 

 called cnrlK)hydmtes. The manufacture of these stan-h-like com- 

 pounds by the appropriation of the carbon dioxid of the air is 



Kl(. 4<>. Mi>anji of ithDwIug iran«pinitlnii. 



