OP THE COTYLEDONS. 99 



getative power of seeds, nor do we know any 

 degree of cold that has such an effect. Those 

 who convey seeds from distant countries, 

 should be instructed to keep them dry ; for 

 if they receive any damp sufficient to cause 

 an attempt at vegetation, they necessarily die, 

 because the process cannot, as they are situ- 

 ated, go on. If, therefore, they are not ex- 

 posed to so great an artificial heat as might 

 change the nature of their oily juices, they 

 can scarcely, according to the experience of 

 Mr. Salisbury, be kept in too warm a place. 

 By the preservation of many seeds so long 

 under ground, it seems that long-continued 

 moisture is not in itself fatal to their living 

 powers ; neither does it cause their premature 

 germination, unless accompanied by some 

 action of the air. 



It is usual with gardeners to keep Melon 

 and Cucumber seeds for a few years, in order 

 that the future plants may grow less luxuri- 

 antly, and be more abundant in blossoms and 

 fruit. Dr. Darwin accounts for this from the 

 damage which the cotyledons may receive 

 from keeping, by which their power of nou- 

 rishing the infant plant, at its first germina- 



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