2 ^ 



1907. I purposely made the examination very late, that is, as late 

 .as April i6th, 1908. The doubly girdled tree contained an 

 abundance of starch in all parts of the stem above the upper 

 ring ; the callus only was, again, free from starch. Below the 

 upper ring, however, down to the base of the tree, reducing sugar 

 and starch were wanting, save in the innermost layers of wood. 

 Here was still a considerable quantity of starch. Above the 

 upper edge of the incision, a large number of roots had been, 

 formed on the upper and lower wounds, but a greater number 

 and longer ones on the upper than on the lower, apparently 

 because there was not so much food available for the lower one. 

 This plant is of special interest as compared with the younger experi- 

 mental plants, previously under our observation, because it shows 

 that the process of draining the reservoirs in the stem will be the 

 slower, the more extensive they are. While in the case of the 

 slender yearling, all starch disappeared from the stem after a 

 period of only 51 days, the thicker, three-year-old plant, after 

 three-and-a-half months, still contained starch in the innermost 

 zones of its wood. From this it is also evident, that the drain of 

 starch evidently starts from the bark. 



The two plants with the bridge of bark on the upper wound, 

 presented the same appearance below the lower incision as No. 

 I., and also above the upper incision. But it stands to reason, 

 that the conditions between the two wounds were somewhat 

 different. For by means of the bridge of bark on the upper one, 

 it had been possible to continue the downward current of sap. 

 On the upper wound itself, starch and reducing sugar were almost 

 completely absent from the wood, that had been formed prior to 

 the operation. On the other hand, starch was abundant in the 

 newly formed wood inside the bridge of bark. And from the 

 ligneous part of this bridge, some starch, though but a small 

 quantity, had penetrated into the immediately adjacent old wood. 

 Below the upper wound down to the lower one, starch was again 

 present in all layers of the stem. It is impossible to draw any 

 conclusions from this circumstance with regard to the quantity 

 of sap that can be transported across the bridge of bark in .1 

 basal direction, as in every case, the- lower girdling had caused 

 an accumulation. Roots had Ixvn formed cliii-lly on the upprr 

 wound, only very few on tin- Lower "nc. 



The conclusions to !>; drawn from all these experiments i an IK- 



