LBCT. II.] VITAL FUNCTIONS OF PLANTS. 53 



fied combinations are the direct result of the living 

 principle, than can be produced by the simple 

 power of affinity when it operates on dead matter. 

 The particular functions of vegetables that depend 

 on vitality are the germination of seeds, the nou- 

 rishment and growth of the vegetating plant, its 

 absorption, perspiration, and respiration, adapta- 

 tion to climate, and resistance of cold during 

 winter. 



The seeds of plants, like the eggs of animals, 

 being endowed with vitality, many of them may be 

 kept for a very considerable time, even for a cen- 

 tury of years; and yet, when they are placed under 

 favourable circumstances, at a proper season, and 

 in a situation where they can receive a sufficient 

 supply of air, heat, and moisture, immediately 

 begin to germinate and grow. If any thing tend 

 to destroy this principle in the seed, instead of 

 germinating, when placed in a situation favourable 

 for germination, it rots ; for, although the vitality 

 which seeds thus possess does not depend on any 

 external circumstances, yet, it may be destroyed by 

 external causes. The time which it may remain 

 latent is not the same in all seeds: some will not 

 germinate unless they be put into the ground al- 

 most immediately after they be gathered ; whereas 

 leguminous seeds may be kept for ages, and yet 

 preserve their vegetative power. The vitality of 

 some seeds is indeed so permanent, that it pre- 



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