Sept. 190(3. J -I 9 Swps and Eceudations. 



been cut away : those trees which have been tapped every alternate day (on 131 occa- 

 sions) have given about 11 lbs. of dry rubber each and only half of the original bark 

 has been removed. 



These photographs show what I mean, very clearly. Tapping at less fre- 

 quent intervals has not only given a higher yield of rubber per tree, within exactly 

 the same period, but there is original bark remaining which will last for another 

 nine months on each tree. We have saved in labour expenses, the yield has been 

 increased, and the trees have been less drastically treated by tapping every alternate 

 day instead of every day. There is some ground for believing that, when incision 

 of the latex tubes is made more perfect than at present, the interval between 

 each tapping operation may, with advantage, become still longer and yet be accom- 

 panied with a further increase in yield and saving of labour. While this is fresh in 

 your minds, let me discuss with you another result which points in the same 

 direction. 



HALF-SPIRAL AND FULL SPIRAL TAPPING, 



You are aware that all the systems of tapping have been tried, experimen- 

 tally, at Henaratgoda. The results are too numerous to be placed before you in a 

 single lecture ; but I wish to point out that those systems of tapping, such as the 

 half-herring-bone or half-spiral, which only allow the operator to tap one side of the 

 tree at a time, though, in our experiments, they have given a lower yield per tree 

 than the full herring-bone or the full spiral methods, yet the yield per unit of excised 

 bark has been higher in the former than in the latter series, and there is plenty of 

 the original bark still tappable. Reluctant as I am to give any appearance of finality 

 to the available results of fragmentary experiments with Para rubber, I cannot pass 

 over those just enumerated without asking you to consider them seriously, as they 

 point to a common agreement explicable from our present knowledge of the origin 

 and construction of the latex tubes in Hevea 6rasi7.ten.sis. If we could only obtain 

 good series of results in different parts of Ceylon, we should soon be able to settle 

 these important questions. 



IMPORTANT POINTS TO CONSIDER. 



To put the explanation in a nutshell, it is, I think, simply this : the latex 

 tubes and their contents require an interval of time to form or accumulate ; if they 

 are tapped too frequently they are less turgid and the yield therefrom is reduced ; 

 if the bark is removed too quickly either by too frequent or too extensive tapping, 

 the material wherein latex tubes might have subsequently developed is com- 

 pletely severed. If you leave the bark on the tree, for a certain interval, probably 

 more latex tubes will be formed, and the yield per unit of excised bark increased. I 

 am sorry to see that my time is up and I must stop. Now, Gentlemen, your turn has 

 come. Your Secretary, Mr. Thornhill, who has taken a great deal of trouble over 

 this lecture, has guaranteed that question time shall be animated and instructive, 

 and having for my main object the stimulating of free, healthy discussion, I trust 

 that you will not hesitate to bring forward many subjects of public importance. 

 We can subsequently consider the microscopic slides which I have brought with me, 

 if any of you care to probe a little deeper into the mysteries of the origin and con- 

 struction of this interesting and important product. (Applause.) 



DISCUSSION. 



The Chairman :— Will any one who wishes to ask a question kindly stand up 

 and ask Mr. Wright. 



TAPPING SYSTEM AND YIELDS COMPARED. 



Mr. Thornhill :— May we ask what where the results from the trees you 

 tapped twice a week in comparison with the trees which gave eleven lb. tapping on 

 alternate days ? 



29 



