In Winter Woods 395 



split the seal above them and open the lenticel 

 once more. And as we have seen, a closing layer 

 or seal of cork has grown across all the scars whence 

 last summer's leaves have fallen. 



Preparations for repose have taken place, not 

 only on the surface of the tree, but in its inner 

 tissues. The fluid which, in summer, mounts 

 slowly from the tiniest rootlets toward the leaves, 

 is the 4< crude sap." It is water, holding in 

 solution chemical substances derived from the soil. 

 In the leaves, as we remember, it is worked over 

 into the "elaborated-sap" which builds up and 

 feeds plant-tissues. And this, creeping blindly 

 from cell to cell, finds its way to the tips of 

 roots and branches where growth is being actively 

 carried on. 



So in latter spring and summer there is a con- 

 stant slow movement of fluids in the trees, first 

 from the roots upward and then from the leaves 

 downward. 



Though this movement is connected functionally 

 with the tree's feeding and digestion, it resembles 

 the circulation of the blood in one respect. Crude 

 sap, like arterial-blood, flows always through one 

 set of channels, while elaborated sap, like veinous- 

 blood, flows always through another. Crude sap, 



