THE LEAVES 53 



IX.— THE LEAVES.— Part I. 



1. How the leaf's air-food is made. Many years 

 ago, in the city of Calcutta, 146 English soldiers were 

 thrust by their enemies into a small cellar. Fresh 

 air could enter by one small window only, and the 

 men fought to get near to this window. In the 

 morning 123 were dead or dying — killed, not by gun 

 nor by spear, but by breathing again and again their 

 own breath ! 



2. Every man, woman, aud child is making this 

 poison-breath. They make it day and night without 

 ceasing, from the moment they are born to the 

 moment of death ; and not only they, but every 

 breathing animal on the face of the earth. Every 

 fire, too, that is kindled, and every light that is lit, 

 adds to this bad air. If nothing were done to remove 

 this poison-breath, the whole air would soon be 

 poisoned, and the world would become as deadly a 

 place for us all as the Black Hole of Calcutta for 

 those English soldiers. 



3. How the poison-breath is removed. But the 

 bad breath which is poison to man is just the food 

 that the leaves need ! Through a thousand tiny holes, 

 too small to be seen, the poisoned air passes into the 

 leaves. This bad air, which is death to us and life for 

 the plants, is called carbon-dioxide, and is made up of 

 carbon and oxygen.* Now, I am going to prove to 

 you that the air that we breathe out is this gas. 



* strictly spealdng, carbon-dioxide is not food, but food-material. The 

 leaf is a factory for making plant-food, and the carbon-dioxide has to be 

 naixed with fluids from the root before plant-food can be made. 



