cr 

 6 



42 



sufficiently " ripened " to carry on adequately the transport of 

 organic material, and until the reservoirs in the wood beneath it 

 have been refilled with starch. A long time, possibly one to two 

 years, will certainly be required for all these operations. This can 

 be ascertained easily by investigations. 



As the flow of organic substances has been checked 

 completely in all those parts of the tree's circumference, in 

 which the vertical channels have been interrupted entirely by 

 tapping cuts, it is furthermore necessary to reject all those tapping 

 methods by which the rectilinear connecting channels between 

 the crown and base of the tree are either too few in number or 

 too narrow in width. For, on account of the extensive renewal 

 of bark and latex, the amount of material required in the base 

 of the tree has increased remarkably. 



Lastly, it is advisable, judging from the results of my 

 experiments, to avoid all tapping methods, by which, although 

 stress is laid on the preservation of sufficiently large vertical 

 strips of bark, yet the incisions are made of such length, that 

 the organic nutrient and constructive substances within the tappin 

 system must travel too great a distance in an oblique or even 

 horizontal direction. For these substances, as I have previously 

 explained, circulate very slowly in an oblique direction. 11 It 

 might thus happen, that & certain want of food might maker 

 itself felt in the portions of bark below the tapping incisions, and 

 that the renewal of latex might be impeded even during the 

 tapping period. 



It" is 'most interesting to see how nearly the tapping methods of 

 the natives in the jungles of America, come up to many of these: 

 requirements, if they are rationally employed. Tapping is there- 

 performed by means of small axes, the blades of which are only 

 1,5 to 3 cm broad. Oblique cuts are made with them right 

 through the bark. Three or four of these incisions, 1,5 to 3 cm 

 wide, are made simultaneously and at an equal height, at a. 

 horizontal distance of 10 to 20 cm, from each other. They begin: 

 as high up on the stem as they can reach, and day by day they 

 make new cuts in a vertical line and at some distance below the- 

 old ones, down to the base of the tree. Then they begin agaia 

 at the top, in the spaces that were left in between. It is obvious 



11 In an oblique upward direction the circulation will in all 

 probability be specially slow. 



