course if these laticiferous vessels do not communicate right 

 through the wood into those of the pith. As, for instance, the 

 laticiferous vessels of tappable Hevea trees are diffused through- 

 out the cortex and the bast (compare the anatomical statements 

 further on), we can with regard to Hevea answer the first question 

 in the affirmative, and must admit, that girdling has an influence 

 onihe_cefilling of the vessels_below_th_girdle. 



I now turn to the second question: In what way can girdling 

 affect the renewal of latex ? It is not difficult to answer. Jf_ 

 latex be produced only in the Ieave3^th^_dscending^curjeftt of 

 latex cannot flow acrosS-the girdle towardsthe 



b^ase of the tree. But if latex is produced in the stem, then, as 

 we have already seen, the downward transport of food supplies 

 becomes entirely suspended by the girdling. In the former case, 

 a refilling of the latex tubes below the girdle will be practically 

 impossible, as long as the girdle has not been bridged over by 

 callus. 



We have every reason to assume that latex is produced, not 

 only in the leaves, but also, or almost entirely, in the stem. 2 

 Some extremely important and interesting observations made in 

 Ceylon and Singapore with regard to the renewal of latex in 

 repeatedly tapped leafless trunks of old Hevea trees, for instance, 

 admit of no other interpretation. 3 But if latex is produced_in 

 the stem, which is j ujidiiubledljL_thjLcase, the nutritive substances 

 required for this purpose must__exist in thg__stem_ in sufficient 

 quantities.. _ If there is a deficiency of them, the_enewal of latex 

 jnust necessarily suffer, the laticiferous vessels cannot Be 



latex, and the supplementary latex may 



possibly deteriorate in quality as compared with the original. We 

 have already seen, that after a complete girdling of a tree a 

 deficiency of nutritive substances must sooner or later make itself 

 felt in the stem below the girdle. The universal injury which 



- None of the observations can force us to acquiesce in the 

 supposition, occasionally laid down, that latex is produced only in the 

 leaves. 



s Compare for instance, J. C. Willis, M. K. Bamber, E. B. Denham. 

 "Rubber in the East." Peradeniya Manuals of Botany, etc., No. I. 

 Colombo 1906. Pages 25, ff. 



H. N. Ridley and R. Derry. Second Annual report on the experi- 

 mental tapping of Para rubber trees in the Botanic Gardens, Singapore, 

 for tlie year 1905 (1907) Pages 24 ff. 



