LECT. II,] VITAL FUNCTIONS OF PLANTS. 57 



in the same soil, if we admit that vegetables are 

 living beings. Is it more wonderful that plants 

 should elaborate the same nutriment into poisons 

 and wholesome food, than that venom is secreted 

 and lodged under the fangs of some species of 

 serpents, whilst nothing of the kind is possess- 

 ed by other reptiles that live on the same kind of 

 food ? In order to disprove that no such selection 

 takes place, it is only necessary to rear any num- 

 ber of different plants in water alone : each plant, 

 in growing, will assume the nature and possess 

 the qualities of the species to which it belongs, 

 whether that be poisonous or salutary : a proof 

 that the qualities of the secretions of plants, like 

 those of animals, are not dependent upon peculi- 

 arities of soil, but on the action of the vital prin- 

 ciple. 



Although every vegetable is a living being, yet 

 all plants do not enjoy an equal share of vitality, 

 nor are they all equally tenacious of life. Some 

 plants die almost immediately, if they be deprived 

 of moisture; whereas others, particularly some of 

 the mosses, may be completely dried, ad pre- 

 served in this state for a considerable time, even 

 for years, and yet retain their vitality; so that the 

 application of moisture will again make them re- 

 sume their verdure and grow. 



On the presence of the principle of vitality de- 

 pends the power of reproducing parts that are de- 

 stroyed. Thus, if a tree be cut down, and the 



