THE SEED AND ITS GERMINATION 11 



as shown in Fig. 3, exhaust the air by connecting the glass 

 tube with an air-pump, which is then pumped vigorously, 

 and seal the tube while the exhaustion is going on. The 

 sealing is best done by holding a Bunsen flame under the 

 middle of the horizontal part of the tube. A much easier 

 experiment, which is nearly as satisfactory, can, however, 

 be performed without the air-pump. 



EXPERIMENT in ' 



Will Seeds Germinate well without a Good Supply of Air? — 

 Place some soaked seeds on damp blotting paper in the bottom of a 

 bottle, using seeds enough to fill it three-quarters full, and close 

 tightly with a rubber stopper. 



Place a few other seeds of the same kind in a second bottle; 

 cover loosely. 



Place the bottles side by side, so that they ■will have tte same 

 conditions of light and heat. Watch for results, and tabulate as in 

 previous experiments. 



Most seeds will not germinate under water, but those of the 

 sunflower will do so, and therefore Exp. Ill may be varied in the 

 following manner : 



Remove the shells carefully from a considerable number of sun- 

 flower seeds.i Try to germinate one lot of these in water which has 

 been boiled in a flask to remove the air, and then cooled in the 

 same flask. Over the water, with the seeds in it, a layer of cotton- 

 seed oU about a half inch deep is poured, to keep the water from 

 contact with air. In this bottle then there will be only seeds and 

 air-free water. Try to germinate another lot of seeds in a bottle 

 half filled with ordinary water, also covered with cotton-seed oil. 

 Results ? 



11. Germination involves Chemical Changes. — If a ther- 

 mometer is inserted into a jar of sprouting seeds, for 



1 These are really fruits, but the distinction is not an important one at 

 this time. 



