102 



[Feb. 1908. 



GUMS, RESINS, SAPS AND EXUDATIONS. 



MGOA RUBBER IN BRITISH EAST 

 AFRICA. 



(Mascarenhasia elastica, K. Sch.) 

 By Otto Stapf. 

 Mr. E. Battiscombe, Acting Conser- 

 vatator of Forests at Nairobi, B.E.A., 

 communicated recently specimens of 

 flowers and fruits of a rubber tree found 

 by him in the Shimba Hills, near Mom- 

 basa. On comparison they proved to 

 belong to Mascarenhasia elastica, K. Sch., 

 a species previously known only from 

 the neighbourhood of Dar-es-Salam, 

 German East Africa, where it is worked 

 occasionally by the natives for a kind of 

 ball rubber called Mgoa rubber in the 

 Zanzibar trade. 



Mascarenhasia elastica was discovered 

 by Dr. Stuhlman in 1898 near Dar-es- 

 Salam, and described and figured by the 

 late Dr. Schumann in the Notizblatt of 

 the Berlin Botanic Garden and Museum, 

 vol. 1, (1899), pp. 268-270. This is what 

 the author says of it as a rubber tree : 

 " Between the villages of Vikindo and 

 Mbaffu there grows in moist places a 

 robust tree which contains rubber latex 

 and yields a superior kind of caoutchouc. 

 The trunk branches usually low down 

 and attains a height of 10m. The pale 

 grey bark is covered with scars from the 

 knives of the rubber collectors, who 

 produce from it large balls of rubber 

 known as Mgoa in the Zanzibar trade. 

 It is not particularly pure, containing 

 fragments of bark, etc." Samples of this 

 rubber received at the Botanic Museum, 

 Berlin, are described by Dr. Warburg 

 (Der Tropenflanzer, III., p. 220) as con- 

 sisting of pale brown drawn-out caout- 

 chouc threads intermixed with small 

 particles of caoutchouc. In 1899 Herr 

 Hedde, Government Gardener at Dar-es- 

 Salam, was commissoned to explore the 

 neighbourhood of Dar-es-Salam and to 

 study the distribution and properties of 

 the tree. Dr. Schumann published an 

 abstract from Hedde's official report in 

 the Notizblatt of the Botanic Garden and 

 Museum at Berlin, vol. III., p. 43. Ac- 

 cording to it Mascarenhasia elastica is 

 fairly common in the district visited by 

 Hedde along streams as well as over 

 underground water. 



It makes flue smooth and straight 

 trunks which are much sought for by 

 the natives, who use them in building 

 their shambas. On the other hand 

 Hedde found the flow of latex too slow 

 to make collecting profitable. He fur- 

 ther adds that the rubber produced does 

 not sell well, possibly, as he says, on 

 account of the crude mode of prepar- 

 ation. Attempts to take Mascarenhasia 

 elastica into cultivation have been so far 

 successful, as the plants grew fast even 

 in dry soil, and flowered and fruited 

 in their fifth year ; but the flow of latex 

 at that age was far too scanty (Der Tro- 

 penflanzer, X., p. 44). 



As other species of Mascarenhasia, 

 natives of Madagascar are said to pro- 

 duce fairly good rubber, known as 

 " Black Madagascar" (Madagascar noir), 

 it was desirable to have an exact ana- 

 lysis of Mgoa rubber. This was made at 

 the Imperial Institute from a sample 

 communicated by Mr. Battiscombe last 

 February to that establishment. Thanks 

 to the courtesy of the Director of the 

 Imperial Institute, we are able to publish 

 the results of the examination of the 

 sample mentioned. 



Report on the Composition of the 

 Rubber from the Shimba Hills, by 

 the Director of the Imperial 

 Institute. 

 Mark and Weight of Sample. — " Rubber 

 from Shimba Hills, East Africa Protec- 

 torate," 104 grams. 



Description. — Single ball of rubber, 

 about 2£" in diameter, evidently formed 

 by winding threads of rubber upon a 

 central mass ; it was light brown, and 

 contained a considerable quantity of 

 vegetable impurity. The rubber was 

 fairly strong. 



Results of Examination : — 





Samples 

 as received. 



Composition 

 of dry rubber. 



Moisture 



% 



io-o 



% 



Caoutchouc ... 



69-0 



76-6 



Resin 



61 



68 



Proteids 



35 



39 



Insoluble matter 



14-4 



127 



Ash 



2-29 



2-54 



