PART II. 

 MY EXPERIMENTS. 



A. Influence of Girdling on the Distribution and Circulation 

 of Sap in the Stem of Hevea. 



I considered it sufficient to make these experiments on young 

 trees. More mature ones I could and would not sacrifice for 

 the purpose, had I done so, I am sure that the results obtained 

 would not have been different. My sole purpose was to ascertain 

 whether girdling has the same effect on the Hevea tree as it has 

 on other trees. As we know by frequent experiments, that other 

 kinds of trees are affected by this operation, no matter whether 

 they are old or young, we are surely right in assuming, that this 

 is also the case with old Hevea trees, if young Hevea trees arei 

 affected. 



In my first experiments I made use of three yearling plants, 

 the height of which was 1,8 m., and which had been raised from 

 seed in the Large Botanic Garden. They were girdled in the 

 lower lignified part of the stem, 50 cm. above the ground. The 

 length of the removed ring of bark was 3 to 4 cm. Before 

 girdling them, the saplings were 3,5 to 4 cm. in girth just below 

 the girdle. The experiment commenced on December 22nd, 1907. 

 One of the plants was cut down for examination on February 

 i ith, 1908, that is after 51 days. The leaves were fresh, the crown 

 had continued to grow, but no new branches had been formed 

 below the girdle. The circumference of the stem above the 

 girdle was now 5,2 to 5,8 cm.; below it was the same as before, 

 3,5 to 4 cm. On the upper edge of the wound, pointing down 

 wards, a thin pad of callus had been formed. Above the girdle, 

 as far as the crown, I found much starch in wood, pith and bark. 

 It was especially abundant in the tissues above thr in< i^ion. Only 



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