August, 1909.] 



105 



Saps and Exudations, 



tity and are said to be like cows that 

 are regularly milked. Of course, judg- 

 ment must be used uot to tap the trees 

 to exhaustion, by which is meant tapping 

 the whole area of the trunk at one Lime 

 and often. By tapping only a small area 

 of the truuk at one time a fresh section 

 of strip can be treated about every fourth 

 or sixth day, or in all about twenty-four 

 times yearly, leaving out the very dry 

 months, the already tapped surfaces 

 being gone over several times during the 

 year. 



Tapping.— Formerly the mode of col- 

 lecting Ceara rubber was as follows : — 

 The loose stones and dirt around the 

 base of the tree were removed by means 

 of a bundle of twigs and large leaves 

 were laid down. The collector then 

 sliced off the outer layer of bark to a 

 height of 4 or 5 feet and the milk exuded 

 by many tortuous courses, a good por- 

 tion of which fell to the ground, When 

 thoroughly dry the rubber was either 

 rolled into the balls or put into bags in 

 loose masses in which form it entered 

 the market under the name of Ceara 

 Scrap. This method was very wasteful, 

 and for want of a satisfactory system of 

 collecting large areas of Ceara trees had 

 been abandoned in various countries. 

 To Mr. Koehler of Lewa, Paugani dis- 

 trict, is given the credit ot devising a 

 method of collecting Ceara rubber which 

 has resulted in establishing a successful 

 and extensive industry in German Bast 

 Africa. The system referred to which 

 is known as the "Lewa" metnod may be 

 described as follows : — About a quarter 

 more or less of the surface of a tree is 

 freely coated with the juice of a Citrus 

 fruit such as sour orange, lemon or lime 

 (to about the height of the tree), the 

 citrus fruit being roughly peeled and cut 

 in two. The bark is then horizontally 

 stabbed with the point of a knife having 

 a sharp thin edge, at distances of about 

 3 inches apart. The milk immediately 

 exudes from the numerous small in- 

 cisions, and at once coagulates on the tree 

 from which it is easily collected about 

 three-quarter of an hour to an hour after- 

 wards, and made into the balls. Sweet 

 oranges may be used, but as the labourers 

 are apt to eat them sour ones are more 

 suitable. Vinegar and weak carbolic acid 

 have been proved to be suitable for 

 coagulating the rubber. Even in a weak 

 state, however, carbolic acid is found to 

 injure the labourer's hands, consequent- 

 ly this is not in favour, even though the 

 acid be applied with a brush. The juice 

 from the sisal plant has also proved 

 fairly successful in the matter of causing 

 coagulation. If no acid be applied, it 

 will be found that much of the milk is 

 lost on the ground. Of the various 

 14 



knives tried, that known as a " Book- 

 binder's" knife has given the most 

 general satisfaction in German East 

 Africa. A chisel-edged knife is to be 

 avoided, as the bark is injured thereby 

 and does not readily heal up- 



The authorities at Amani have found 

 that the latex-ducts of the Ceara tree 

 run principally perpendicularly, hence 

 the need for making the incisions hori- 

 zontally. About thirty average-sized 

 sour oranges or lemons are said to be 

 sufficient to coagulate a pound of Rubber. 



Other methods of tapping are being 

 experimented with in German East 

 Africa, but for utility and simplicity the 

 "Lewa" method has so far proved the 

 most satisfactory and is readily under- 

 stood by the labourers. The matter of 

 obtaining a sufficient supply of citrus 

 fruits is, however, of great importance. 



A good man can easily collect 1 lb. or 

 more of rubber per day, but a general 

 average would be about J a lb, to fib. 

 per labourer daily. 



The early morning is the best time to 

 collect the rubber, which, after being 

 made into a ball, can be placed in papaw 

 or banana leaves for conveyance to the 

 store, where it is washed and squeezed 

 in clean water to remove as much as 

 possible of the impurities. It is then 

 placed in an airy position to dry out of 

 the direct rays of the sun, and when 

 practically all moisture has been ex- 

 pelled it is ready for shipment. 



Where proper machinery is available, 

 the raw rubber is subjected to a 

 washing, rolling and drying process, 

 with the result that all impurities are 

 quickly removed and the rubber rendered 

 ready for shipment in a short time. 



A ball of freshly collected Ceara 

 rubber weighing 805 grammes was seen 

 subjected to the washing, rolling and 

 drying process referred to, at Amani, 

 and finally weighed 111 grammes. 



Yield of Trees.— These vary con- 

 siderably, though the following figures 

 supplied by an extensive grower in 

 German East Africa may prove of 

 interest : — 



2nd to 3rd year ... | lb. 



3rd to 4th year ... f ,, 



4th to 5th year ... | 



5th to 6th year ... £ to 1 lb. 

 Taking one tree with another a good 

 yield of rubber per tree in full yield per 

 annum would be from f to 1 lb., though 

 individual trees frequently very largely 

 exceed this quantity, instance — On the 

 Lawa estate there are several Ceara 

 rubber trees from 9 to 10 years old 

 which have produced from 10 to 14 lbs., 

 German, each per annum. Again, six 



