THE SEED AND GERMINATION 41 
Oxygen.—Now make experiments to show whether 
air, or rather oxygen, is required. 
Experiment 3.—Place bean and other seeds in a 
bottle of water which has been recently boiled for 
some time to expel air. See that the water reaches 
right to the mouth of the bottle and then cork it 
GERMINATION 
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Rubber cork 
=== NO GERMINATION 
BARLEY GRAINS 
PYROGALLIC ACID GERMINATING. BARLEY 
FIG.22. FIG23 FIG 24 
tightly. As a control (ie. standard of comparison) 
place seeds in unboiled water, and, leaving the bottle 
uncorked, from time to time bubble air with a pair of 
bellows or a syringe into the water. In the first bottle 
there will be no sign of germination, while in the second 
the seeds will sprout a little, though, owing to the 
limited supply of air, germination will not be very 
vigorous. We thus see that air, or one or more of its 
constituents, is necessary to germination. 
Experiment 4 (Figs. 22-24).—Obtain three U tubes, 
place in one end of each, on moist cotton wool or rag, 
