India Rubber and Gutta Percha Cultivation in Ceylon.
From the Report of the Director of the Royal Botanic Gardens.
India Rubber. (The import of Caoutchouc into Great Britain during 1882 amounted to nearly 20,000,000 pounds.) Ceara.—In Ceylon a planted area of 977 acres is credited to this kind of rubber, but it has not yet appeared among our exports. Since it has been ascertained that the quality is excellent, (I am informed that as much as 4s. a pound has been obtained for Ceylon Ceara rubber.) cultivators have been endeavoring to discover a means by which the milk can be obtained at a cost sufficiently low to give a return, but without, as yet, encouraging results. The removal of the outer separable bark, as practiced in the experiments referred to in my last report, has been objected to on the ground that the bark formed in its stead is of a different character, very hard and inseparable from the green layer a second time. Instruments have therefore been devised for bleeding without such removal. A knife with two parallel blades, which took out a strip of bark, has been modified into one in which the very sharp cutting edges meet to form a V, the basal angle during use being at the cambium. Another invention avoids all cutting, being a double spur-like wheel with sharp but guarded points which puncture the bark without further injury. The milking (one can scarcely call it tapping) has also been practiced on trees of various ages and at different intervals and seasons. While it is found that the yield of individual trees varies extremely, (This is to be expected; for it should be recollected that the 'milk' in plants is quite distinct from their sap, and is contained in special channels. It has no nutritive function, but, like the alkaloids in cinchona, is rather of the nature of an excretion. Its removal, therefore, per se, inflicts little or no injury on the plant.) none of the experimenters is satisfied that the small quantity obtainable by present methods is sufficient to make the cultivation profitable at the existing price of rubber. Mr. Wall, however, who states that hundreds of young trees have been bled daily with the "pricker" for some weeks, and that thus a cooly can collect about half a pound of dry rubber per diem, thinks that, if trees will bear this treatment for two hundred and forty days in the year, the cultivation would be remunerative. It appears evident that milking must be repeated at frequent intervals, and (as often already pointed out) the cultivation be conducted on a large scale. Much of the 35,000 acres in private hands in Ceylon, at present growing nothing but Lantana and other weeds, is suitable for this hardy plant, which costs nothing to cultivate, affords a substance of a value which is continually increasing, and awaits only the discovery of a process by which the latter can be cheaply and exhaustively extracted.
Castilloa Rubber.—From a single tree at Pérádeniya a considerable crop of seedlings was raised. The fruits ripened at the end of May; they are little, white, pointed nuts, about half an inch long, covered by a bright orange pulp, and some twenty to thirty are crowded together on the fleshy flattened scaly receptacle, forming collectively what is called a compound fruit; about half of the fruits ripen and contain each a single seed. I have already expressed my opinion as to the suitability of this tree for cultivation by a Forest Department as a source of prospective revenue; and as comparatively few of the plants were disposed of to private persons, I made an endeavor to get plantations of this valuable tree formed at Eatna-pura and Kalutara. The plan was sanctioned by the Governor, and I gave the necessary instructions; but after three months' delay it was discovered that the trifling sum necessary could not be provided.
The growth of the largest Castilloa tree at Henaratgoda is, at a yard from the ground, 30 ¼ inches, an increase of 4 ¼ inches during the year.
Para Rubber.—Nine trees flowered at Henaratgoda in March, and the fruit ripened in August, About two hundred and sixty seedling plants were raised, many of which have been disposed of to persons desirous to try the cultivation. Our largest tree is now 30 inches in circumference, an increase of 4 ½ inches in the year.
Eighteen plants of another species of Hevea, H. Spruceana, were received from Kew in October. This is a native of British Guiana, where it is generally known by its Arawack name "Hatie." It has been studied in its native forests by Mr. Jenman, who sent us a plant in 1881, which unfortunately died. Dr. Spruce also collected it on the Amazons. It is closely allied to H. brasiliensis, and grows under quite similar conditions. The specimen of the rubber sent home by Mr. Jenman for report appears to have been unfortunately mixed with some impurity which prevented its value being accurately ascertained. The plants have been put out mostly at Henaratgoda, and are doing well.
Some seeds of this species were also kindly sent to the garden by the Manager of the Ceylon Company, Limited, in July, but were quite dead. It is useless to attempt to import seeds of this description from any distance, as they lose their vitality in a few days.
Other Rubber Plants.—Landolphia Petersiana, one of the East African rubbers, has flowered during the year, and L. Kirkii is now in bud at Henaratgoda. Two plants of Tabernaemontana crassa are now doing well. Among seeds received from Mr. L. Wray, of Perak, were some of "Gutta Singret," which appears from leaf specimens, also sent, to be a species of Chilocarpus, another climbing apocynaceous genus. Its rubber is not of a good quality, and is chiefly used for adulteration. A few plants were raised and are planted at Henaratgoda.
Gutta Percha.—A valuable series of dried herbarium specimens, of wood, and of the commercial products of the various gutta-producing trees of Perak, has been sent by Mr. L. Wray, Jr. (collecting for Sir H. Low), which has enabled me to determine with more certainty the species we possess is a living state. He has also sent me a copy of a report to Sir H. Low on the gutta question, which contains some valuable additional matter to that collected at Kew and published in the report of that institution for 1881, pp. 38-47.
I am now satisfied that the identification of "Gutta Sundek" with Payena (Ceratephorus) Leerii, on which doubt has been thrown, is correct. Mr. Wray describes the tree as partial to swampy places near the coast, even where the water is salt; the wood is hard and close-grained, and the fruit sweet and eaten by the Malays. There is an inferior variety, with a thinner bark, known by. its longer leaves. Our plants at Henaratgoda have grown quickly; their rate of growth is much more rapid than the species of Dichopsis.the largest are over 8 feet high; the tallest at Peradeniya is 6 feet 2 inches.
The young plants of "Gutta Taban putih" grow very slowly. The good dried specimens now sent show this to be distinct from Dichopsis Gutta, but I am not able to say to which species of Dichopsis they should be referred. This tree is found in the lower hills, 1,800 to 2,500 feet, and not in the plains; the gutta is a dirty white (whence the name putih = white), coagulates slowly, and does not thoroughly soften even in boiling water. Mr. Wray also distinguishes a small-leaved variety with a longer fruit.
The specimens further confirm our previous knowledge that the best and most frequent sort of gutta percha of commerce, "Gutta Taban merah," is the produce of Dichopsis Gutta. Our trees of this are now nine years old, but the tallest is but 9 feet high. According to Mr. Wray, this tree attains 100 to 200 feet in height, with a clean, straight trunk of 4 to 5 feet diameter, flanked at the base with large thin buttresses; the bark is ⅓ to ½ an inch thick, brown-red in color, and flakes off; the leaves are much narrower on young plants than old ones, the flowers are white, and the seeds yield an oil, solid at ordinary temperatures, but used for cooking. The gutta is at first white and cream-like, but becomes pink, and ultimately brownish red ("merah" = red), and this color is strongly imparted to the water in which it is washed. There is a variety of this species affording a paler gutta called "Gutta Taban sutra" ("sutra" = silk), which is found at a higher elevation (500 to 600 feet).
Other sapotaceous trees affording gutta, of which specimens have been sent by Mr. Wray, are "Gutta Taban simpoo," Dichopsis Maingayi, Clarke.the product of which is also sold as "gutta putih"—and "gutta garru," Bassia Mottleyana, De Vriese, which gives a white hard sort, only used for mixing with other kinds. He also sends examples of the curious substance called "Gutta Jelutoug," used for adulterating gutta percha. It is obtained from a very lofty apocynaceous tree allied to our "Rukattana" (Alstonia scholaris) (This appears to yield a somewhat similar substance at Singapore, called Gutta Pulei.) and recently named Dyera costulata by Sir J. Hooker.
The yield of the gutta percha trees seems to be very small—less even than the rubber trees. Thus from a tree of D. Gutta, thought to be over one hundred years old, and over 100 feet high, Mr. Wray succeeded in extracting, by the ordinary native method, of felling and ringing the trunk and branches, only 2 lbs. 5 ozs. of clean gutta. Of "Gutta Taban putih," a tree 10 inches in diameter, gave 2 lbs. 11 ozs., and one of Payena Leerii, 2 feet 8 inches in circumference, only 6 ½ ozs. Mr. Wray has satisfied himself that only about 1/38 part of the gutta percha actually in the bark is extracted by this method, and he believes that by pounding and boiling the bark the whole could be obtained. As the question of the supply of gutta percha is becoming a pressing one, it is to be hoped that experiments on a large scale may confirm this opinion. To quote Sir J. Hooker (Kew Report, 1881, p. 38), "the time cannot be far distant when the natural sources of gutta percha will be definitely used up." In view of this contingency it behoves the governments of those few British colonies—Ceylon being one—in which the trees will grow, to lose no time in establishing plantations, which must in the future become a valuable source of revenue. But in this colony, neither in this case nor in the case of India rubber, can anything be done until a proper forest conservancy is established.—Phar. Jour. and Trans, June 28, 1884, p. 1052.