256 



THE INDIA RUBBER WORLD 



[May I, 1906. 



distances, however, are objectionable, because a large num- 

 ber of cuts appears to detract from the healing powers of the 

 tree and the more cuts, the greater the chances of the tree 

 being injured by the borer. Another point in the number ol 

 cuts is the time and labor in making the cuts. Six cuts to 

 a tree is twice as much labor as 3 cuts, hut if it does not give 

 twice as much rubber it would be cheaper to make ,, cuts ai d 

 tap a larger number of trees in a day. 



The tapping is now being done with only 3 cuts per tree ; 

 one at the base, one at 5 feet from the ground, and one half 

 way between these. Tapping above 5 feet necessitates the 

 use of ladders, and this would mean more labor and would 

 hardly pay with young trees. I believe the making of 4 

 cuts, the top one 6 feet from the ground, would give enough 

 more than 3 cuts to pay, if it is not too great an injury to the 

 tree. 



The first signs of healing appear between one and tw.o 

 weeks after the cut is made, and in two months at the latest 

 the cut is well healed. In time the whole cut will fill with 

 new material which contains latex and can be tapped again 

 if necessarj'. Another strong reason why the tool should 

 cut to the cambium is that not only does the shallow cut 

 miss cutting some " milk tubes " but it misses a very large 

 proportion of the tubes. The milk tubes are formed by the 

 cambium in layers. The ones closest to the outside bark were 

 formed when the tree was very young and small in circum- 

 ference. At that time the patches of tubes were close to- 

 gether. Since then the same number of tubes had to spread 

 out and cover a circumference of, say 18 or 20 inches. The 

 spaces between these tubes are filled by medullar)^ ra3^s 

 which run from the pith outward through the wood to the 

 outside bark. Therefore the outermost layers contain very 

 few milk tubes, the next more, and so on, until the inner- 

 most layer has the most since it was formed when the cir- 

 cumference was greatest. This is borne out in facts. A 

 much larger j-ield is actually obtained by cutting into the 

 cambium than by cutting almost into it. 



Another thing to be avoided is cutting too deep. When a 

 cut goes through the cambium into the wood the healing com- 

 mences at the edges of the cut cambium, and has to spread 

 slowly, making new cambium before it can make new bark 

 or wood. If too much wood is exposed in this case it will 

 often dry up before the cambium can heal over and in that 

 case it never heals. I have seen an old machete cut with a 

 half inch of wood exposed, with the bark thoroughly healed 

 all around it. I was told that it had been that wa\- without 

 healing for two years. 



As to the time to tap, there appears to be no reason why 

 the trees should not be tapped at any time during the rain}- 

 season. I should imagine that the dryest season in March 

 and April would be a poor time, but I haven't been heredur 

 ing that season. Rain generally makes the milk rather 

 watery and makes it flow more freely, but I have never seen 

 it so watery that it would not pa}- to tap, except in a tree 

 which had been recentlj- tapped. Tapping in heavy rain would 

 not do, as it would wash the latex, which does not flow into 

 the cups and might fill up the cups and spill the latex in 

 them. 



Temperature affects the flow of latex very noticeably. The 

 yield of rubber is much greater in the early morning than at 

 any other time of the day, and always decreases toward noon 

 and increases toward night. This is not so noticeable on 



cool cloudy days. It would probably not be so noticeable in 

 a sh idy plantation and for this reason some people have 

 claimed that shade grown trees yield more. I belie \'e that 

 the reason temperature affects the flow is because a large 

 amount of the water is evaporated and the latex is more solid 

 and does not flow so freely. 



Experiments of others have shown that young trees and 

 younger parts of old trees contain a large percentage of resin 

 in their rubber. I have made one observation which sug- 

 gests a reason for this. In cutting a temporary branch, or 

 leaf stem, it is noticeable that the latex comes very close to 

 the outside bark and that there appears to be a second ring 

 of tubes in the inner bark. Microscopic examination of these 

 parts shows a large number of collendyma cells close to the 

 outside bark. These cells are similar to bast fibers, but the 

 thick part of the walls is not uniform. Collendyma cells are 

 never formed by older trees except in their young parts. I 

 think it possil)le that by these collendyma cells carry latex 

 which is richer in resins than ordinary latex and which may 

 possibly be entirely resin. Of course these collendyma cells 

 remain in the plant as it grows older but form a very small 

 proportion of its tissue at that time. It is possible that rub- 

 ber or resin maj- have some chemical relation to the cellu- 

 lose of which the thick walls of both collendyma and bast 

 fibers are formed. A FORESTER. 



Bluefields, Nicaragua, February. 1906. 



CEYLON RUBBER EXHIBITION. 



A RUBBER exhibition, under authority of the Ceylon 

 ■'-^ government, will be held in the Rojal Botanic Gar- 

 dens at Peradeniya, beginning on September 13 and remain- 

 ing open for a fortnight. This will be the first exhibition 

 of its kind and it is hoped vi-ill mark an epoch in the history 

 of rubber. The exhibition will comprise anything and 

 everything that has to do with rubber, and exhibits are in- 

 vited of crude rubber, however produced ; of rubber in vari- 

 ous stages of manufacture ; any forms of machinery de- 

 signed for use in connection with rubber; "and anything 

 else, likely to prove of interest." The exhibition will be 

 held at the most central and familiar place in Ceylon, and is 

 intended to attract all rubber planters from the Far East, 

 and particularlj' those of Ceylon and the Federated Malay 

 States, who thus far have made more progress in this new 

 interest than has been made elsewhere. 



Dr. John C. Willis, director of the Ceylon botanic gar- 

 dens, in the oflicial circular announcing the exhibition, 

 states that " though the exports of plantation rubber from 

 Ceylon and the Malay States as yet are inconsiderable, they 

 are doubling annually and will in about seven years time 

 probably reach 10,000,000 or 15,000,000 pounds, and increase 

 rapidly after that, in 15 years from now probably exceeding 

 the exports of Brazil." It is intimated that manufacturers 

 in future will find their chief dependence for rubber to be 

 upon the plantation product, "and wild rubbers will be 

 driven off" the market, excepting perhaps the Para rubber of 

 Brazil, for which there is likely to be some use and a remu- 

 nerative price for a long while yet. " 



The circular intimates that important development in the 

 matter of machiner}- is to be looked for in two respects : (i) 

 in designing mechanical appliances for the preparation of 

 plantation rubber, in which connection an important begin- 



