VITALITY OF SEEDS. 27 



and wheat ordinarily live as many years, we do not 

 fully know. If we say that the oiliness of the nuts 

 is the cause of their quickly becoming rancid, what 

 shall we say of the oily seeds of the cabbage tribe, 

 some of which are noted for their long vitality? 

 It is enough for our present purpose to know that 

 there exist recognized differences depending on the 

 nature of the seed. That the coating of seeds is an 

 important factor in resisting decay is seen by the 

 quickness with which corn meal or wheat flour 

 deteriorates, as compared with the whole grains 

 from which they are made. Everyone knows too 

 that the conditions under which seeds are kept have 

 much to do with the duration of their vitality. 

 The most favorable conditions for prolonging life 

 in the seed are the opposite of those which favor 

 germination. Thus, to keep seeds we put them in 

 a dry place. Dampness, even if it does not induce 

 the germination of the seed itself, favors the growth 

 of fungi which destroy its vitality. Thus it is that 

 in the damp climate of England it is more difficult 

 to keep seeds than in this country. But moisture, 

 if sufficient to exclude the air, or accompanied by 

 too low a temperature for the germination of the 

 species, may favor prolonged vitality in seeds. 

 Under whatever conditions seeds are kept, however, 

 there is a continual loss of vitality from the time 

 that they ripen. It is true that some seeds ordi- 



