CAOUTCHOUCS OR INDIARUBBERS (Gastilloa). 45 
it will stand. A few trees of about 3 feet girth gave an 
average of 5 ounces of rubber each from one day’s tapping. 
Probably three or four tappings might be done every year 
without serious injury, but this remains to be investigated. 
The tree is not very resistent, and in some cases at Henarat- 
goda has died back completely, apparently as the result of a 
number of tappings carried on four years ago. Trees in the 
Matale District, about twelve years old, have yielded 1^ to 2 
pounds of rubber a year. 
It is sometimes stated that rubber may be obtained from 
saplings or from the young twigs, thus saving many years in 
obtaining a return, but Parkin’s experiments showed that in 
Ceylon at any rate the latex in young stems contains no 
caoutchouc, but a sticky substance like bird-lime, which he 
terms viscin. 
The best Castilloa rubbers appear on the market as sheets, 
and are valued next to fine Para. Ceylon samples have 
obtained 3s. per lb. at a time when fine Para was valued 
at 4s. 2 d. 
GEARÀ RUBBER.— Manihot is a genus of the family 
Euphorbiacece , to which belong also several other rubber- 
yielding plants. It comprises about eighty species, natives of 
S. America ; among others is the manioca, tapioca, or cassava 
( M.utilissima , Pohl.), so largely grown in Ceylon (see chapter 
VI.). M. Grlaziovii , Miill.-Arg., the Ceara rubber, is a native 
of Brazil, and is especially common in the Province of Ceara. 
Plants and seeds were collected there by Cross, and arrived 
at Kew in the end of 1876. On 15th September, 1877, 50 
plants were sent to Peradeniya, and put out there and at 
Henaratgoda. These came on rapidly, so that in the follow¬ 
ing year seeds from them were sent to Burma, Calcutta, and 
Madras. In 1879 a few seeds were distributed to planters in 
Ceylon, and in 1880 24,550 seeds and 1,879 plants were thus 
disposed of. By the end of the following year the demand for 
seed from the gardens had almost ceased, planters having 
