Set II. Agriculture and Vegetation. 123 



SECT. II. 



Of the food of vegetables. 



WE now come to treat of that impor- 

 tant queftion, What is the food or 

 nourifhment of plants ? a queftion which 

 has been much handled, but not fufficient- 

 ly afceftained yet. It has even been made 

 a queftion, Whether each plant has not its 

 peculiar and proper food, which it chufes 

 amongft the reft, from fome elective power 

 inherent in its roots ? 



THOSE who take this fide of the queftion, 

 aflert, that the advantage arifing from the 

 change of fpecies is a certain proof of this ; 

 for if the fame nourishment ferved all 

 grains, the fame grain would thrive in the 

 fame ground, as well as another j that al- 

 though wheat will not fucceed in the fame 

 ground for two years fuccefiively, yet it 

 will bear another grain very well; and 

 that the different nature and properties of 



vege- 



