THE VITALITY OF THE PLANT 13 



simply deflects the energy into another channel. 

 '2. The argument from plant physiology is 

 equally important. It is a common assertion 

 that cutting off a limb is an injury because it 

 removes a given amount of tissue in the pro- 

 duction of which the plant expended effort ; 

 that is, that pruning exhausts the plant. This 

 statement assumes that a plant has a certain 

 fixed vitality, from which a given amount is 

 withdrawn whenever a portion of the plant is 

 cut away. I might illustrate this by supposing 

 that a plant has an initial vitality represented 

 by the figure 10 ; then, if one- tenth of the top 

 is removed, there is left a vitality of 9. But 

 this assumption is wholly gratuitous. The vi- 

 tality of a plant is very largely determined by 

 the conditions under which it grows the charac- 

 ter of the soil and treatment ; and, I may add, 

 that as plants have no nerves, they cannot die 

 of shock, as we sometimes hear it said. Every 

 fruit-grower knows that two trees of the same 

 initial vigor may differ widely from each other 

 in thrift and healthfulness at the expiration of 

 five years, if given different soil and care. If 

 the plant is very largely what its food supply 

 and other environments make it to be, if it is 

 constantly renewed and augmented, then the 

 removal of a portion of it cannot destroy its 

 vitality unless the removal is so great as to 

 interfere with the nutrition of the remaining 



