Gums, Beains, 



104 



[February, 1910. 



ping to death and thinning out begin 

 at the age of six years. In order to 

 obtain as large a surface for tapping as 

 possible, aerial roots are propagated on 

 the remaining trees. In tapping, a 

 number of oblique parallel cuts are 

 made on the trunk and main branches. 

 The same tapping instrument is used as 

 with Cctatilloa. The cuts which act as 

 channels are likewise cut with a sharp 

 knife, The latex is collected in cups 

 with some water, filtered, and the rubber 

 separated by boiling. As the flow of 

 latex in six-year-old trees, where closely 

 planted, is only small, the whole of the 

 rubber is allowed to solidify in the 

 wounds and is then obtained as scrap. 

 Ficus scrap is very much better than 

 Cnstilloa scrap. It is of a reddish colour, 

 very solid, elastic and dry. It realised 

 only l£d. per lb. less than Ficus sheets 

 in block form. In consequence of this, 

 most of the Ficus rubber has been pre- 

 pared as scrap, and for this purpose the 

 incisions are preferably made in a 

 horizontal direction. 



The yield of six-year-old closely-planted 

 trees amounts by thinning-out to about 

 2 oz. per tree. Trees of the same age 

 standing singly produce some three to 

 four times this quantity. Approximately 

 the same proportions occur as with 

 Caatilloa, for instance, isolated six-year- 

 old trees gave over 4 oz., whilst closely 

 planting specimens gave only 1 oz. per 

 tree, 



FUNTUMIA ELASTICA, 



This species has been cultivated ex- 

 perimentally in all German Colonies, but 

 only in Cameroon to any great extent ; 

 about 5,000 acres have been planted there 

 with this species. It is generally planted 

 very close, but probably here also an 

 initial distance of less than 10 ft, between 

 the plants offers- no special advantages. 



From the tapping of wild Funtumia 

 trees, it is known that this species yields 

 latex more readily than others, and 

 that it is almost as sensitive to drastic 

 tapping as CastUloa. Tapping of the 

 cultivated tree has occurred experiment- 

 ally in Cameroon ; these trees, however, 

 do not stand closely planted, but singly 

 or in rows, and the results must be 

 judged accordingly. It can be assumed 

 that from 3 to 3£ oz. are to be expected 

 from six-year-old trees planted at good 

 distances from each other, and 1 to 2 oz. 

 from closely planted trees. 



The method of tapping practised in the 

 last experiments with Funtumia differed 

 from all other methods, in that verticle 

 incisions the whole length of the trunk 

 were made. As to its advantage over 

 the herring-bone system, further obser- 



vation and a more extended series of 

 comparative tapping trials are first 

 necessary. 



The rubber is procured by boiling the 

 latex after diluting it with water ; treat- 

 ment with hydrofluoric acids yields a 

 better product. Although Funtumia 

 rubber is at present inferior in quality 

 to that of Hevea and Ficus, and at most 

 is equal to that of CastUloa, still it may 

 be confidently anticipated that with 

 more suitable preparation it will yield a 

 good serviceable product. 



Manihot Glaziovii. 



It will be more difficult to find a 

 process in East Africa by which the 

 medium quality rubber from this species 

 can be converted into a suitable quality, 

 corresponding to the demand of manu- 

 facturers. By the tapping method 

 generally in use in East Africa, the 

 rubber is exclusively obtained as scrap, 

 as the latex flows too scantily from the 

 incisions in the bark for it to be collected 

 in cups. The tapping process there- 

 fore consists of making punctures in 

 the bark with knives, in a definite 

 manner, after it has been coated with 

 a coagulating medium, The exuding 

 latex coagulates immediately and the 

 resulting rubber is obtained as scrap. 

 This scrap is inferior in quality to 

 CastUloa and Funtumia rubber. In 

 British Central Africa good results are 

 obtained by tapping Manihot according 

 to the method customarily employed 

 for Hevea, which depends upon good 

 response, together with the use of the 

 herring-bone incision and by moistening 

 the incision with ammoniacal water ; 

 for instance, in a tapping period of 

 over nine months, 15 oz. of pure rubber 

 per tree were obtained. Likewise in 

 Togo, by means of the herring-bone 

 system, trees, not yet six years old, 

 produced in five days, on the average, 

 12 oz. of rubber as latex, and barely 

 five year old trees averaged 2| oz. 

 There are single old trees which yield 

 up to 12| lbs. of rubber a year, whilst 

 on the average only about 275 lbs. can 

 be reckoned from an acre of 400 trees. 

 As the Manihot becomes ready for tap- 

 ping much earlier than all other kinds 

 of rubber trees, its cultivation offers 

 many advantages. 



Amongst other rubber-yielding plants 

 which are cultivated experimentally here 

 and there in the German Colonies may 

 be mentioned the Manihot dichotoma, 

 Manihot piahuyiensin, Ficus Bigo, Ficus 

 Schlechteri, ' Foresteronia floribunda, 

 various Landolphia species, Masca- 

 renhasia elastica, and so forth. How- 

 ever, all these species have very little 

 interest for cultivation on a large scale. 



