CH. XIII] INDIARUBBER, GUTTAPERCHA, AND CAMPHOR 129 



as an indication of how rapidly this new industry is becoming 

 important. 



1901 66 cwt. London price 4s. l\d. per Ib. 



1902 189 4s. Od. 



1903 389 5s. Od. 



1904 676 6s. Od. 



1905 1401 6s. 4d. 



1906 3705 55. lid. 



1907 7093 3s. lOd. 



Next to the rubber industry of the east, the most important 

 cultivation is that of Mexico, in which about 80,000 acres are 

 covered with Castilloa elastica. This tree is but little in favour 

 in Ceylon and the other countries with cheap and plentiful 

 labour, but in Mexico, where the labour is both scanty in 

 amount and very expensive, this tree, which is there native, is 

 very much liked, as at one tapping it gives a larger amount of 

 rubber than the Hevea. As labour is so scarce that the trees 

 cannot be tapped more than say once in two months, this suits 

 very well, and the fact that Castilloa trees cannot be tapped 

 much oftener than that without injury does not matter. The 

 best tools for tapping this tree have yet to be discovered, as has 

 also the best method of treating the latex. It is quite possible 

 that treating the latex with a centrifugal machine just like 

 cream may prove to be a very good method of preparing the 

 rubber, though indications are not wanting that so pure a 

 caoutchouc as is thus made is lacking in strength. This method 

 was discovered several years ago by Mr Biffen, but has not yet 

 been successfully put to any practical use. 



Ceara rubber, Manihot Glaziovii, has not yet been made the 

 basis of any important cultivation industry, though there is 

 a small amount in Ceylon, German East Africa, etc. It grows 

 like a weed, and comes into bearing in a few years. There 

 being no wound response in this tree, the yield is small, and in 

 spite of its suitability to many districts where Para rubber will 

 not grow, it has not yet been much taken up. A good tapping 

 tool for this tree is still a desideratum. 



Lately 1 three new species of Manihot, M. dichotoma, M. 



1 Ule, " Kautschukgewinnung und Kautschukhandel in Bahia," Notizbl. 

 Berlin, v. 1908, p. 5. 



w. 9 



