THE SEED AND ITS GERMINATION 9 



as shown in Fig. 3, exhaust the air by connecting th&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 II 



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 ivith 

 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 ivill have the same 

 conditions of light and heat. AVatoh 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. II may be varied in the 

 following manner. 



Reiuove the shells carefully from a considerable number of sun- 

 flower seeds.-"^ 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 ^\'ater, with the seeds in it, a layer of cotton-seed 

 oil about a half inch deep is poured, to keep the water from con- 

 tact 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? 



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

 mometer is inserted into a jar of sprouting seeds, for 



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

 this time. 



