Gums, Resins, 



[Jul*, 1908. 



in regard to tapping tools suitable for 

 this tree. The Hevca planter re-opens 

 the incision at frequent intervals, and 

 his plan is to do this by cutting away as 

 small amount as possible of the cortex. 

 The paring process is adopted for this 

 purpose, and the many different tools 

 employed in this connection show a wide 

 variation. Among these may be men- 

 tioned the Golledge tapping knife, 

 which is a modification of a chisel ; the 

 "V.D.K." knife, patented by Gustav 

 Van den Kerkhove ; Dixon's knife ; the 

 Para chisel ; and various others. (Nearly 

 thirty different rubber tapping tools were 

 demonstrated.) 



The principal idea in tapping a rubber 

 tree is to make it possible to extract the 

 maximum amount of latex with the 

 minimum injury to the tree, as the ex- 

 traction cannot be done without injur- 

 ing the tree. This injury need not and 

 should not be more than a very tem- 

 porary one, and the trees as such should 

 not perceptibly suffer. We know that 

 the more bark we excise the more time 

 is needed by the tree for replacing the 

 cortex. We should therefore make a 

 cut which takes away as little bark as 

 possible. On the other hand, we must 

 make a groove big enough to allow the 

 latex to run. If the groove is too narrow, 

 the latex clogs and is apt to coagulate 

 in the incision. If the grove is too 

 shallow the latex is liable to run over the 

 edges and is lost. Then, again, if the 

 groove or the incision is too deep, we have 

 cut, through the bark, the cambium into 

 the wood. In this case we have greatly 

 injured the tree, as we have disconnected 

 the tissue which carries the food mate- 

 rials of the tree from roots of the crown 

 where they are prepared for the use of 

 the plant. It is evident that the tree 

 will suffer from such a treatment. The 

 more we have cut away of the cambium 

 the longer time will it take for the tree 

 to recover and for the incision to heal. 

 Most of the knives, of the type of the 

 farriers knife, lend themselves to too 

 deep cutting in the hands of an unskilled 

 tapper. Many of these tapping devices 

 have some kind or another of gauge to 

 determine the depth of the wound, and 

 theoretically these "guides" work well, 

 but 1 have seldom found a tapper who 

 did not cut into the wood. 



The latex tubes occur in the layer 

 between the cambium and the outer 

 bark, but as they originate in the cam- 

 bium and are constantly being added to 

 from this tissue, it is impossible to draw 

 a line of demarcation between these 

 tissues. It is therefore incorrect to talk 

 about tapping a tree by cutting through 

 the inner bark without touching the 

 cambium, Either we do not cut entirely 



through the inner bark or we cut into 

 the cambium. In the former case we 

 do not cut all the latex tubes and there- 

 fore do not obtain the maximum amount 

 of latex. In the latter case we get all the 

 latex, but we injure the cambium. The 

 question then arises How are we to get 

 all the latex without seriously injuring 

 the cambium? Experiments have 

 shown that, if we cut through the cam- 

 bium with a sharp knife blade, without 

 taking away any part of the cambium, 

 the cells of this last tissue that have 

 been injured continue in growth and 

 the wound begins to heal over within 

 24 hours, and takes only a short time to 

 heal completely. We should therefore 

 have a knife which opens a groove suffi- 

 ciently largely to permit the flow of latex, 

 but which only penetrates the harder 

 part of the cortex. It should at the same 

 time cut through the softer parts of the 

 cortex without making a deep groove, 

 and it should, in fact, open all the latex 

 tubes. In practice this last can only be 

 done by cutting through the cambium. 

 To accomplish this the "Alpha" knife 

 was developed by me, and the first 

 sample made shoAved that the theory 

 was sound. The amount of latex ob- 

 tained was larger than with any other 

 knife tried in the experiments, and they 

 number over two dozens. Another 

 feature of this "Alpha" knife is that it 

 has two handles which gives the operator 

 an opportunity to work with both 

 hands, thus being able to direct the in- 

 cision according to will. The first blade 

 of the knife or the "groover" makes a 

 shallow incision in which the latex runs. 

 The second blade or the "cutter" is 

 placed so that it pares off a thin slice of 

 the lower side of the groove leaving a 

 clean cut, and as it cuts deeper and the 

 operator rests on this blade it will cut 

 through to the wood. In this way it 

 cuts all the latex tubes and at the same 

 time the cambium, but it does not take 

 out any part of the softer tissues. I 

 mentioned before that a wound penetrat- 

 ing into the cambium, with a single 

 knife blade, such as this " cutter," does 

 not cause any permanent injury to the 

 tree and heals very rapidly. 



This last mentioned tool can be oper- 

 ated by a comparatively unskilled work- 

 man, and as he can use both hands he is 

 able to do much more rapid work than 

 with single-handed tools. Experiments 

 have shown that one man can with this 

 tool cut incisions at the rate of over 1,000 

 current feet per day. Taking four in.- 

 cisions of a length of one foot per each 

 tree, one man can thus tap 250 trees per 

 day. The best results obtained in Mex- 

 ico with one-handed tools have been 120 

 trees per man, while the average is 70» 



