Where the Tree Is Alive 



This section of the trunk of a small tree is pictured in 



such a way as to expose the Cambium layer, just beneath the 



outer bark. In this layer are located all the protoplasmic cells, aside 



from those in the leaves, that are really -alive. A portion of the 



woody tissue Just beneath the Cambium conveys the watery solution 



upward from the roots; but the return flow of sugary sap takes place 



solely in the Cambium layer, where also the protoplasmic or life 



activities go on. through which the tree grows; growth itself 



being due to the deposit of what is virtually wast* 



material from the cell. The central wood 



fibers of the trunk aie totally dead. 



