XXXIV.] VEGETATIONS 



is by seed : some, however, are raised by a part of 

 the root of the old plant set in the ground, as po- 

 tatoes f otheFS-, by new roots propagated from the 

 old one, as hyacinths and tulips; others by 

 cutting off branches and putting them into the 

 ground which will there take root and grow, as 

 vines; and others are propagated by grafting, 

 and budding, or inoculation* 



What is most difficult with respect to Plants (and 

 what has been the subject of much controversy, 

 though yet undetermined), is to explain the man- 

 ner in which they receive tlieir nourishment. The 

 earth has not so much to do in this business as has 

 been commonly supposed. This is known from 

 the experiments of Mr. Boyle and Dr. Woodward. 

 These gentlemen raised several Plants in earth- 

 watered with rain or spring water, and even distil- 

 led water; and upon weighing the dry earth, both 

 before and after the product! an of the Plants, they 

 found that very little of it was diminished or takem 

 up by the Plant- 



Jf the earth contributes so little towards the 

 production and nourishment of Plants, it seems 

 natural to apprehend that water must be much 

 concerned; and that this is the case in great mea- 

 sure is evident, from the quantity of water which- 

 most plants require to keep them in a state of 

 health and vigour. But there is some other agent 

 besides water; else, how can the growth of Plants 

 in sandy desarts where it seldom rains be account- 

 ed for, and these Plants such as cuntain juices i 

 great abundance ? 



Dr. Hunter^ 



