Gums, Resin*. 



21S 



| Sept. 190H. 



wrong, that if we could extract the latex by some method which would not destroy 

 the cambium or the bark (cortex), we might be able to almost drain the tree dry and 

 still leave it standing. Some Para rubber trees have been known to be incapable of 

 yielding latex during certain years ; subsequently they gave latex in quantity. The 

 milkless state did not appear to seriously affect the trees. 



SPARK THE BARK, BUT GET THE LATEX. 

 In my opinion, it is not in the extraction of latex that the harm is done so 

 much as in the removal of the bark containing that substance. The bark or cortical 

 tissue, which is removed in tapping operations, contains organised systems of 

 elements which are of vital importance to the plant, and on their health and con- 

 tinuity depends the perfect distribution, mainly from above downwards, of the food 

 materials elaborated in the leaves. As a store house and conducting channel the 

 cortex is of vital importance to the plant, and if it is removed too quickly the life of 

 the tree may be endangered. The rapid stripping of the bark is an unnatural pro- 

 cess, analagous, perhaps, to the treatment meted out to cinchona trees — though they 

 did not nourish long— but not comparable with the natural peeling away of dry bark. 

 During ordinary tapping operations the cortical cells are excised while they are 

 in a living condition, and are entirely removed at a time when they contain reserve 

 food intended for the use of the plant ; it also differs from the natural peeling of 

 the bark, in so far as the average operator exposes the inner and more delicate and 

 vital components of the cortex and cambium to atmospheric influences. Such treat- 

 ment does affect the vigour of the trees, and if cortical stripping is effected much 

 more frequently than once in three or four years, I anticipate trouble in the future. 



TOO FREQUENT TAPPING LOWERS THE YIELD. 



Apart from the consideration of the after effects, there are others of very 

 great importance to every planter who has to get the best yield posssible. The 

 discovery, if so it can be named, is the outcome of observations made at Henarat- 

 goda, where the trees have been tapped at all intervals ranging from once per day 

 to once per mouth, on definite but different systems, and I have brought with me 

 some photographs to illustrate what I wish to say. The results of experiments 

 outlined to determine quite different points have shown a common agreement in so 

 far that, when tapping has been done too frequently or too extensively, the yield 

 of rubber has been seriously reduced, and the bark or source of future latex has gone. 

 Many experiences have been already recorded in which surprise is evinced that 

 well-developed trees in one country have not given the same yield of rubber as less 

 vigorous specimens in Ceylon ; in some of these cases the poorer yield from the 

 better developed trees can be associated with the too rapid excising of the bark, 

 and the sooner we all realise that the bark is really the " mother of rubber," and 

 that its removal means a reduction in subsequent yields, the better for all concerned. 

 It is, no doubt, encouraging to know that rubber can be extracted from the usual 

 bark shavings, but a high yield therefrom is not what rubber planters should 

 specially search for. 



TAPPING EVERY DAY AND ALTERNATE DAYS. 



One might at first conclude that, since the Para rubber trees rarely ever run 

 absolutely dry, and most of them (no matter how roughly they have been handled) 

 appear to contain an inexhaustible store of latex, the more frequently the trees are 

 tapped the larger the quantity of latex obtainable. Bat curiously enough the series 

 of experiments which I have in mind show the very opposite result, and though they 

 may or may not be exceptions, they deserve consideration. The trees in one area 

 have been tapped every day from September, 1905, and those in another group every 

 alternate day from the same date. The trees which have been tapped every day (on 

 294 occasions) have given about 9 lbs. of dry rubber each, and all the original bark has 



