46 REPORT ON THE CAOUTCHOUC OE COMMERCE. 
plants, could be grown around existing trees and thus save much 
time, trouble, and expense, and would begin to yield at a much 
earlier date, the Urceola elastica , Roxb., being said to be fit for the 
tapping operation at three years old. 
Conclusion. 
On the whole question of the trees yielding Caoutchouc, its pre- 
paration, &c. there is still much to be learned. In this report I have 
incorporated all the essential points affecting the question, which I 
have been able to gather during several years study of the .subject — 
searching at home and instituting inquiries abroad in order to 
obtain valuable and trustworthy information. I should in conclu- 
sion beg to recommend that the subject should be studied on the 
chief spots where the trees are found. Especially would I 
particularize the Amazon districts as likely to yield much valuable 
information to one going prepared on the subject, as to trees 
yielding Caoutchouc (for there is much to be learned on this branch 
of inquiry alone), its preparation, and other inquiries which would 
suggest themselves to a person well versed in the subject. I 
therefore beg to add a scries of instructions, rather as indicating 
types or classes of questions requiring elucidation. In Assam M r. 
Mann would be well qualified to seek answers to these queries -if 
time and opportunity be granted him for the purpose. 
SPECIMENS AND INFORMATION DESIRED 
ON CAOUTCHOUC AND THE TREES PRODUCING IT. 
1* Samples of crude juice, without any preparation whatever, 
care being taken to place the same, immediately on collection in 
air-tight vessels in order to guard against any spontaneous change 
taking place. If two such specimens can be sent, to one should be 
added a small quantity of liquor ammonise. Care should be taken 
to exclude light. (Strong tinned cans would be convenient vessels 
to send the milk.) 
2. Samples of Caoutchouc, prepared in as many different ways as 
possible, such. as with the aid of (a) artificial heat; (b) hot water; 
(c) natural heat ; (d) alum ; (e) liquor ammonise ? ; (f) acetic 
acid ? ; (g) any plant, and also sending a quantity of the plant' so 
used; (h) fresh water; (i) saltwater; (j) burning sulphur, taking 
care to note the time occupied, and all the steps of each process, 
using in every experiment an uniform quantity of the same milk. 
