108 FIELD, FOREST AND FARM 



hair. Those are the openings into so many broken 

 ducts. Everything in the plant, absolutely every- 

 thing—root, stalk, wood, bark, leaves, flowers, fruit, 

 seeds, no matter what — is composed of a mass of 

 cells, fibers, and ducts. 



"That understood, let us consider the root of the 

 plant. In its new parts, at the tip-ends of its finest 

 ramifications, tip-ends that we have called spongioles, 

 it is composed of cells just formed and consequently 

 tender and fitted for absorbing easily the moisture 

 in the soil. Spongioles, then, fill themselves much 

 as sponges would do. That done, conduits offer 

 their services for conveying the liquid to the top of 

 the plant: they are the ducts just referred to, and 

 comparable here to the water-pipes in our own foun- 

 tains. But if in fountains water runs by its own 

 weight, going from the highest to the lowest point, 

 it is not so with the liquid absorbed by the roots, a 

 liquid running from below upward. What then is 

 the force that makes it ascend? 



"This force is in the buds or, to speak more cor- 

 rectly, in the leaves. Each leaf is the seat of an 

 active evaporation whose object is to rid the plant 

 of the great quantity of water required for dissolv- 

 ing in the soil and then conveying to the leaves the 

 nutritive substances present in the soil. This evap- 

 oration leaves a void in the cells that have given 

 up the evaporated water. But this void is imme- 

 diately filled from the neighboring cells, which give 

 up their contents and receive in turn the contents 

 of the next lower layers. From cell to cell, from 



