ON THE COMMERCIAL KINDS OF INDIA-RUBBER. 21 
slabs, round balls, and * tongues.” These last are about four inches 
long and a little thicker than your thumb. Borneo rubber is bad 
enough to handle, as regards its smell, but African rubber has a spe- 
cial oue of its own. What tales could it tell, if it could use its 
“ tongue,” of persons going into a sale-room, thinking perchance of the 
cholera returns, sniffing and saying, “Dear me, why you've dead 
ratsl" The boards are taken up, but no dead rats or draius are dis- 
covered, and so the poor rubber gets the blame, and is finally put out 
on the roof to air. When old, it turns black and loses much of its 
fetid smell. It is of a yellowish-white colour, very adhesive and 
very slightly elastic. It is the poorest of our commercial kinds, its 
value only being about 11d. to 1s. 1d. per Ib, One hundred tons are 
reported to have been used for home consumption in 1866. 
By some this rubber is considered the produce of Sycomorus 
Guineensis, Miq., Hooker's * Niger Flora, p. 523. (Ficus Brassii, R. 
Br.) It was first described in * An Account of the Edible Fruits of 
Sierra Leone," from the Journal, etc., of Mr. Geo. Don, A.L.S., 
Joseph Sabine, Esq., F.R.S. (Trans. Hort. Soc. Lond., vol. v. p. 448). 
However, no mention is made of any caoutchouc being produced by it. 
In the Kew Museum there is a specimen of caoutchouc collected by 
Dr. Kirk in the Livingstone Expedition, from a species of Carissa, 
but it has no resemblance to the commercial kind. The first trace of 
this rubber I have seen was a specimen of the wood of the tree with 
the rubber exuding from it, brought from the west coast of Africa by 
Dr. Horton, and shown to me by Mr. J. R. Jackson at the Kew Museum 
on October 26th. Subsequently Professor Oliver kindly furnished me 
with the following note on the subject :—‘ Dr. Horton brings from 
West Tropical Africa a specimen of rubber and fragment of plant 
affording it. This, there can be little doubt, belongs to Apocynacee, 
but, being destitute of flowers and fruit, it is impossible finally to de- 
termine. It is hairy, and in this character resembles one or two 
African species of Sírophanthus." This specimen of rubber is un- 
doubtedly identical with our commercial kind, and we must wait 
anxiously till proper specimens are forwarded to ascertain the plant 
producing it. 
IV. AUSTRALIAN KINDS OF INDIA-RUBBER. 
I received to-day (November 14th) a fragment of rubber from Aus- 
tralia, but do not know by what tree it is produced. 
