THE WORK OF STEMS 



257 



answer his question we take a cutting, preferably of 

 Willow, about five inches long (cut so that the lower 

 cut surface comes just below a bud) and ring it just 

 above the lowest bud by removing a ring of bark 

 about a quarter of an inch wide, so as to lay bare 

 the wood. 



We now place the cuttings in a jar of water so that 

 they stand upright, about half submerged (the ring 

 or girdle should be under water). Under these con- 

 ditions they put forth roots and shoots, whose relative 

 development above and below the ring will indicate the 

 relative supply of nourishment. The experiment must 

 be continued for some weeks. 



Inasmuch as in ringing we cut away the rind or 

 cortex in which the starch and sugar chiefly travels, 

 we may institute a control experiment to see how far 

 this affects the result by ringing some cuttings in such 

 a way as to cut the rind only but not the soft bast. 

 At the end of the experiment, test for starch. Does it 

 accumulate in the cortex above the cut? 



Ringing is often practiced in grape culture. The 

 branch is ringed some distance below the young cluster 

 cf grapes, and the food which would otherwise pass down 

 through the cortex and soft bast is retained and used 

 by the growing fruit, which grows to an unusual size. 



In testing trees for food substances, we find con- 

 siderable starch in the wood, and on tracing it back 

 find that it travels thither in the so-called silver 



