GAS WHICH PLANTS GIVE OFF 125 
Now the carbon, hydrogen, and oxygen in the carbonic 
acid do not hold on to each other very tightly. When 
they get into the green of the leaf and the sunlight 
flashes in, it drives them apart very easily, and they 
hurry to form new associations or compounds which 
the sunlight cannot break. Perhaps it is because they 
hurry so, that the new associations they make are not 
permanent; at all events these are soon broken and 
others formed, until finally the elements unite in such 
a way as to form sugar in the leaf. The symbol for 
this sugar is C,H,,0,. To get this it was necessary 
for six parts of the carbonic acid to combine. This 
would take all of the carbon and all of the hydro- 
gen, but there would be twelve parts of oxygen left 
over. This oxygen is then set free. From the great 
amount of carbonic acid which is broken up in the 
leaf under these conditions, a considerable amount of 
oxygen would be left over and set free from the plant. 
After the sugar is formed, one part of water (H,O) 
goes out of it, leaving C,H,)0;, which is the symbol 
for starch. 
