of a rubber tree Ficus Elastica that it is not possible by means 

 of those laticiferous vessels which are situated in pith devoid of bast 

 to effect a sap-transport across portions of branches, which have 

 been girdled down to the wood. However we must bear in mind, 

 that not all laticiferous plants need necessarily follow the same 

 rule. It will therefore be necessary to submit all the various kinds 

 of rubber plants to a series of special experiments. I take this 

 opportunity to mention that on Hevea my experiments of girdling 

 have had the same negative result, that Kniep obtained by his own 

 on Ficus. They will prove, that at least in the case of Hevea, all 

 the same rules for the transport and storage of sap in the stem 

 hold good as in the case of other trees. 



C. Influence of Incisions on the Production of Latex in the 



Bark. 



In order to form a correct estimate of the suitability of any 

 tapping method, it is important to ascertain not only as I pointed 

 out at the commencement of this chapter to what extent tapping 

 will injure the vitality of the tree, but it is also necessary to 

 find out in what way it affects the renewal of bark and of 

 latex. The answer to the latter question will for the present 

 depend entirely on the solution of the former, and therefore the 

 solution of the first problem, being the fundamental one, is the 

 one which we must endeavour to obtain. We shall have no 

 difficulty in comprehending this, if we again make the experiment 

 of girdling the basis of our deliberations. Let us, therefore, 

 suppose, that cutting down to the wood, we have made a complete 

 girdle round a rubber tree, the pith of which is devoid of bast, 

 and that during this operation there has been an abundant How of 

 latex from the parts of the stem below the girdle. The important 

 questions for us to solve are, whether and in what manner girdling 

 will affect the re-filling of the partly drained laticiferous vessels 

 in the parts of the stem below the ring. Whether or no such 

 an influence will make itself felt, will depend solely on tin- 

 distribution of these vessels in the tissues of the tree. If the \ essels 

 only, or chiefly, occur in the cortex and the bast, the iiilluei). e 

 is a matter of course; if they are also t<> any extent situated in 

 the pith, an influence on the formation of latex in the tubes of 

 the cortex and of tin- bast belmv the girdle i> only then a matter of 



