Vol. XII. No. 297 



THE AGRICULTURAL NEWS 



303 



was forthcoming to indicate the possibility of such a means 

 of spread. It may be noted too that another fungus was 

 noticed growing from the cuttings of the tissue. This 

 organism was found to be quite distinct from the Colletotri- 

 chuni, and its hyphae possessed clamp connexions. 



IXO< ILATIONS so FAR LNSUrCESSFUL. 



Rorer made fifty inoculations with the Colletotridium 

 huincui.i, but none were successful, nor were the inocu- 

 lations made with the Basidiomycelous fungus in any way 

 different from the checks. These latter inoculations were 

 of course made with mycelium, since no spores could be 

 produced, but it is pointed out that from the fact that 

 infection evidently takes place in the bud just as it begins 

 to develop, successful inoculations cannot properly be made 

 until spores of the fungus are discovered. 



METHODS OF CONTROL. 



As regards remedial measures, Rorer appeals to 

 disapprove of the inkapping method, and suggests thorough 

 spraying with Bordeaux mixture in the place of inefficient 

 spraying with copper sulphate. Whilst in Suriname, Itorer 

 recommended the employment of a better type of spray pump. 



RUBBER, 



VARIETIES OF PARA RUBBER TREES. 



The following article, by the Director of Agricul- 

 ture, appears in the Agricultural Bulletin uf the 

 Federated Malay States (June l!tl3): — 



The India liuhher Journul of March ], 1912, contained 

 an interesting abstract of part of the report of the Com- 

 mission appointed by the Brazilian Government to visit the 

 chief plantation rubber-producing countries of the East 



A statement contained in the report, which aroused 

 a certain amount of interest in Malaya, was to the effect 

 that all the plantation rubber trees in the Orient belong to 

 an inferior vnriety of Hevea, known in Brazil as the 'white' 

 variety, while the best rubber in Brazil is produced by trees 

 of the 'black' variety. The only exception, it was stated, 

 were some 200 trees at Pasir Oeijing in Java 



In view of the high price our plantation rubber has 

 always fetched, and the statement by Dr. Huber, at 

 >'ew York, that our trees were of the same kind as those 

 producing the best rubber in Brazil, the above statement did 

 not cause great uneasiness. It seemed, however, better to 

 make whatever enquiries were possible and see to what 

 extent the statement was true. 



Dr. C. J. J. van Hall, Chief of the Division of Botany 

 I in the Department of Agriculture, .lava, has very kindly 

 made eiujuiries regarding the trees at Pasir Oetjing with 

 the following results; — 



'All the Hevea trees on this plantation, except the 

 oldest ones planted thirteen years ago, originate from seeds 

 from Valambrosa and other estates in Malaya. No differ- 

 ence can be distinguished between these trees and trees 

 on other e^^tate8 in Java. The thirteen-year-old trees 

 number about l,.0OO, they were raised from seed bought 

 from Godefroy-Lebeuf (Paris), who oli'.ained the seed from 

 Brazil. 



'Dr. Rutgers went to Pasir Oetjing to investigate these 

 trees. Their appearance is a little different from the coiumon 

 type,thoir bark being very smooth, or m re greyish or whitish 



than is usual; the bark is thin. The yield from the trees i-< 

 poor and decidedly below the average. In the leaves there is 

 about the same \ariation as there always is among Hevea 

 leives, and nothing particular could be found. 



'It thus appears that a number of trees exist at Pasir 

 Oetjing which had a different origin from the common type, 

 and the appearance of which is slightly different. Their yield 

 is poor. If a special name is given to this variety, it should 

 be "white" not "black".' 



In addition to what has been said above, the following 

 conclusions arrived at by Sir 1). Prain, Director, Royal Botanic 

 Gardens, Kew, will be of interest: — 



'It is clear that the scientific botanists who are at work 

 in Brazil have not yet been able to come to a common under- 

 standing as to the relative economic value and status of the 

 three sorts of "seringueira" spoken of in your letter as red, black 

 and white varieties. But the evidence, such as it is, points 

 to only the red as being distinguished botanically from 

 typical //. brasiliensU. The black and the white, so far as 

 the available evidence goes, are not varieties in a scientific 

 sense; they appear only to be different states of the same 

 type, the particular state which is of most value being that 

 which grows on higher and drier land than the other. 



'This last statement of the Commission thus qualified i.s 

 in complete accordance with what has always been under- 

 stood with regard to llevea lirasilienns, and we have no 

 reason to doubt the strict accuracy of this statement (see 

 Wickham, Para Ruhbei\ pp •") and 61) that the whole of the 

 Hevea seed originally introduced to the East came from 

 trees which grew under the conditions thus indicated by the 

 Brazilian Commission.' 



Use of Sodium Bisulphite in the Preparation 

 of Plantation Para Rubber.— Messrs Beadle, Stephens 

 and Morgan, writing in the India Rnhher World for August 

 2, 1913, state that they have tested plantation Para, 

 prepared with sodium bisulphite, and have found it to be of 

 a slightly better quality than rubber, with which the 

 chemical has not been used. It is particularly suitable in 

 the preparation of pale rubber, and the authors take 

 objection to the commonly made statement that the 

 chemical bleaches the rubber. It really only inhibits 

 darkening by arresting fermentative changes. Nor does the 

 reagent make the rubber brittle as it is often said to do. 

 Rubbers prepared with sodium bisulphite, however, tend to 

 dry more slowly than tho.se not so treated. When small 

 quantities of the chemical are used, the delay occasioned in 

 this respect seldom amounts to longer than two days. The 

 authors believe that the .slightly better quality is due to this 

 longer drying period. 



Migration of Sulphur in Vulcanized Rub- 

 ber. —The fact well known to rubber manufacturers, that 

 sulphur is capable of wandering from one layer of rubber 

 to another which ht s a different sulphur content, led 

 H. Skellon, B.Sc, to investigate the matter, and his results 

 are described in the Indii Rithhtr Jonnial (August 9, 1913). 



Briefly the experiments consisted in placing together 

 layers of rubber of known sulphur content When the 

 sulphur content was identical, no migration occurred, but 

 when different the migration took place with equal facility, 

 either upwards or downwards. Equilibrium is very quickly 

 arrived at in the two sheets during vulcanization, and then 

 the concentration of the free sulphur in rubber is the same 

 in the two sheets. Vulcanization is regarded as melting of 

 the sulphur, solution of the sulphur in rubber, and slow 

 combination of the sulphur with the rubber. 



