June 1, 1917.] 



THE INDIA RUBBER WORLD 



549 



vated land of the island is under rubber. Kelani Valley and 

 Kalutara are the most important rubber districts, the areas being 

 53,235 and 50,193 acres, respectively. Few new plantations have 

 been opened and it is hardly expected that any considerable 

 enterprises in this direction will be undertaken in the immediate 

 future. 



The exports of rubber for 1916 again showed an increase, 

 being S4-/2 million pounds, which is 8 million more than for 

 1915. America again headed the list of buyers with 27 million 

 pounds, or half of the total shipinents. The United Kingdom 

 came second, having bought about 23; 4 million pounds. 



Whereas Ceylon pale crepe rubber compared very favorably 

 with that from other sources, Ceylon ribbed smoked sheets are 

 often over-smoked and not too well graded. 



NODULES IN THE CORTEX OF HEVEA TREES. 



This is the subject of an investigation by G. Bryce, B.Sc, as- 

 sistant botanist and mycologist, the results of which are reported 

 in Bulletin No. 28 of 'the_ Ceylon Department of Agriculture. 

 These swellings on Hevea stems, not the result of tapping wounds, 

 and often termed "burrs," take the form of small woody bodies 

 of varying shape and size. Although comparatively rare in 

 young trees, they appear more frequently in trees which have 

 been tapped for some time. In their younger stage nodules may 

 cause only a slight external swelling, but after several years' 

 growth they give a characteristic gnarled, knotted appearance to 

 the stem and may interfere with tapping or even render it im- 

 possible in trees badly aflfected. 



Of their development, and ideas regarding causes Mr. Bryce 

 writes : 



.A.bout the cause of the production of nodules much difference 

 of opinion prevails ; several explanations have been advanced, 

 but none so far has found general acceptance. A nodule at first 

 is a little isolated body of woody tissue lying in the cortex usually 

 about the size of a "pea" when first observed, and easily "shelled 

 out" with a penknife. There is little to indicate its presence at 

 this stage, occasionally a small protuberance or a slight cracking 

 of the bark externally. In later stages these "peas" increase to 

 the size of a "hen's egg" ; or many "peas" fuse together and form 

 an irregular mass ; or, again, large sheets of woody tissue are 

 produced. At the same time growing points originate, which grow 

 inwards and unite with the stem wood, and thus ultimately the 

 nodular. masses become connected with the stem at many points. 

 As the nodules grow larger the stem becomes gnarled ; the cortex 

 cracks and latex oozes out; finally, the entire stem to a height 

 of 5 or 6 feet from the ground is affected. In this condition it 

 is impossible to carry on tapping, and the tree is useless. 



Mr. Bryce finally summarizes the results of his investigations 

 as follows : 



(1) Nodules are produced in the cortex of Hcvca BrasUiensis 

 as the result of an alteration in the latex vessel content. 



(2) This alteration has not been connected with the attack of 

 any parasitic organism, but appears rather to be due to physiologi- 

 cal changes in the latex. 



(3) The tendency to suffer alteration in the latex vessel con- 

 tent appears to be confined to certain individual trees which have 

 a predisposition to develop this condition. 



(4) Four types of nodule have been distinguished : 



(a) Nodules formed round altered latex vessels. 



(b) Nodules formed round lesions in the cortex into 

 which latex has oozed and coagulated. May occur in 

 Hevca tree. 



(c) Nodules formed round areas into which latex has 

 oozed and coagulated; the coagulated latex occupies 

 the intercellular spaces without lesion of tissue. May 

 occur in any Hevea tree. 



(d) Nodules formed under unknown conditions round 

 areas of cortex from which latex may be entirely 

 absent. Rare. 



(5) Globular shoots formed by the subsequent growth of 

 latent buds after these have lost their connection with the stem 

 occur in both tapped and untapped trees. They arc distinguished 

 from nodules by the absence of a core, and they never form large 

 masses of woody tissue as nodules do. 



{6^ Nodules of (a) type do not occur on untapped trees. 



(7) Nodules occur on Hevea in its native habitat in Brazil : 

 and in tropical America and the Eastern tropics where it has been 

 grown in plantations. 



(3) The percentage of trees which develop nodules is very 

 small. 



(9) Tapping appears to induce nodule formation in predis- 

 posed trees. 



(10) This abnormal condition is apparently not infectious. 



MODE OF OCCURHENCE OF HEVEA LATEX VESSELS, 



The distribution and mode of occurrence of latex vessels in the 

 cortex are obviously of great importance as factors influencing 

 the amount of latex obtainable by tapping. Since Scott's investi- 

 gations in 1885 many other rubber experts have made important 

 researches, but up to the present no record exists of any investi- 

 gations into the number of cylinders at different heights of the 

 stem in mature trees, or of any seasonal variation in these num- 

 bers. In order to elucidate this and several other obscure points 

 in connection with the subject a more detailed investigation than 

 any hitherto was undertaken by G. Bryce, B.Sc, and L. E. Camp- 

 bell, B.Sc, F.I.C., respectively assistant botanist and and mycol- 

 ogist, and rubber research chemist of the Ceylon Department of 

 Agriculture. Several untapped trees planted in 1905 at the Ex- 

 periment Station, at Peradeniya, were chosen, and the results 

 were confirmed by examination of trees growing on plantations 

 in several districts of Ceylon. 



The findings, as stated in Bulletin No. 30, follow : 



(1) Considerable variation occurs in the number of stone 

 cells in the cortex of different trees. There is consequently 

 variation in the degree of disintegration of the latex vessels. 



(2) There was evidence of the diminished production of latex 

 vessels in Februarv and March, when the trees were changing 

 leaf. 



(3) The number of rows of latex vessels in the cortex de- 

 creases with the height above ground level. 



(4) The distance between the rows of latex vessels did not 

 usually increase in proportion to the distance from the cambium. 

 The average of the distances between the rows was approximately 

 0.2 millimeters. 



(5) Well-defined cases of connections between neighboring 

 rows of latex vessels were not observed. Several examples of 

 bifurcation of rows were, however, noted. 



(6) The course of the rows may not be invariably regular and 

 parallel. Sometimes the rows undulate, and the same neighboring 

 rows vary in distance apart at different points. 



(7) In general the thicker the cortex the more rows of latex 

 vessels did it contain, though the increase was not great. 



(8) The distance from the cambium of the first interrupted 

 row was approximately 1.5 millimeters; this represents the inner 

 cortex or food-conducting tissue of the tree, and should be left 

 untapped. 



THE SITUATION IN MALAYA. 



By a Special Correspondent. 

 A RATHER warm discussion of the question of granting 

 ^""^ land to aliens took place at a recent meeting of the 

 Planters' Association of Malaya, held at Kuala Lumpur, Fed- 

 erated Malay States. 



It was maintained that although from the point of view of the 

 local government it would be unbusinesslike to refuse capital 

 of any sort directed to the opening up of land, planters, as 

 such, and as Britishers, objected to a "lot of aliens, be they 

 Americans, Danes or what not," coming into the country at a 

 time when circumstances demanded British money and control 

 elsewhere. Past experience had taught what difficulties were 

 to be expected from allowing aliens to monopolize business, and 

 it was especially undesirable that German capital should enter, 

 which would undoubtedly result from the admission of American 

 capital. Meanwhile, 25,000 acres of land had already been 

 granted to an American concern. 



The quesUon was then raised whether, if .'\mericans were 

 allowed ^ to open large plantations and to develop them at 

 express speed the government would order that they import 

 their own labor. 



It was finally agreed to forward to the Chief Secretary of 

 the Federal Council an expression of the .Association's objec- 

 tion to the "alienation of land at a time when British capital 

 and superintendence is unavailable for opening up such land." 



