298 LUTHER BURBANK 



take in water at once give up a portion of it to 

 their neighbor cells, and these in succession pass 

 it on to their neighbors. Thus, through an end- 

 less series of reactions between the cells the sap 

 is carried up in the living wood next to the bark 

 of the tree and ultimately to the leaves. 



NATURE'S BUCKET BRIGADE 



The process is not altogether unlike the activi- 

 ties of a fire brigade in the rural districts, where 

 a line of men is formed from the fire to the near- 

 est well, and buckets are passed from hand to 

 hand. 



If the fire is in the upper story of a building, 

 men on the ladder may similarly hoist one bucket 

 after another from hand to hand. And in this 

 case it is obvious that there is no question of a 

 column of water to exert pressure. The water 

 is transported in individual buckets each one 

 independent of the others. 



And it would appear that the case of the water 

 in the plant cells is closely comparable. Each 

 pair of cells constitutes a system more or less in- 

 dependent of all the others. 



The forces of osmosis, operating between each 

 pair of cells, are in command of the situation and 

 so break the continuity that all semblance to a 

 continuous column of water is lost. 



