33 - 



Bowman parer and the Bowman pricker were used alternately 

 (on the diagram shaded by alternate lines and dotted lines). The 

 tapping period extended from November 8th to April nth. The 

 tree was then cut down and examined for starch and reducing 

 sugar with the following result : above the uppermost incision, 

 both bark and wood were very rich in starch. But there was 

 no trace of either reducing sugar or starch in a zone of bark 

 5 cm wide, immediately adjacent to the top end and the sides 

 of the tapping cut. Nor was starch or reducing sugar found in the 

 bridges of bark between the incisions ; on the other hand, starch 

 was everywhere present in the wood. Below the last and lowest 

 tapping spot, the presence of starch could be proved only in 

 the bark at a distance of 15 cm. from the last tapping wound. 

 On the incisions themselves, starch and reducing sugar were 

 absent both from the bark and from the outermost zones of wood, 

 1,5 to 2 cm thick. In all other parts of the tree there was 

 abundance of starch. 



That starch was completely wanting in the bridges of bark 

 between the tapping spots, was probably due to the fact, that 

 owing to the transport in an oblique direction, not enough could 

 be substituted to replace the amount used up in this region. 



This experiment teaches, that tapping cuts of this description 

 can at most have only a local influence on the descent of organic 

 food substances towards the base. 



3 



