44 EXPERIMENTS WITH PLANTS 



Bean, Castor- bean, Sunflower, etc? The fruit of the 

 Cockle-bur contams two seeds; it is said that one of 

 these will germinate the first year if given the right 

 conditions, but that the other will not germinate 

 before the second year. 



How long will seeds live if not awakened ? The 

 numerous accounts of seeds, three thousand years or 

 more, taken from mummies and made to germinate 

 are untrustworthy; but there is fairly good evidence 

 that seeds which have been deeply buried for many 

 years can germinate under the proper conditions. 

 It has been found that seeds which have apparently 

 lost the power of germinating can sometimes have 

 their vitality restored by soaking in certain ferments. 



A rapid method of testing seeds which is often em- 

 ployed is to place them in water; those which sink 

 are declared good, while those which float are 

 rejected. Test some seeds in this way, and plant 

 both those which float and those which sink (the 

 same number of each) and record what percen- 

 tage of each germinates. (This test may work fairly 

 well for some kinds of seeds, but prove of no value 

 in other cases.) Seedsmen find it necessary to test 

 the germinating powers of their seeds by accurate 

 methods. For this purpose, the seeds are placed in 

 shallow trays on moist cloth, paper, porous earthen- 

 ware or plaster of Paris and kept at a constant tem- 

 perature at the degree which is ascertained by experi- 



