ELASTIC GUM. 297 



they are green on the upper part, and white beneath. The seeds 

 are three in number, and contained in a pod, resembling those of 

 the palma Christi ; and in each of them there is a kernel, which 

 being stripped and boiled in water produces a thick oil or fat, an- 

 swering the purposes of butter in the cookery of that country. A si- 

 milar juice was obtained by M. Poivre some years ago, from a tree in 

 the lisle of France ; and various milky juices of nearly the same 

 properties have been extracted from other plants, as the cecropia 

 pellata, the ficus Indica, religiosa, &c. 



In the fifth volume of the Asiatic Researches, Mr. Howson has 

 given an account of a tree which he discovered in Prince of Wales's 

 island ; and from which he obtained caoutchouc, in almost every 

 respect, exactly similar to that which we receive from America. 

 This tree Mr. Howison denominated the elastic gum vine ; but Dr. 

 Roxburgh, who procured specimens of it from Sumatra, and whose 

 botanical description of it appears in the volume just referred to, 

 has classed it under the name of urceola elastica. Those who have 

 not an opportunity of consulting the Asiatic Researches, may find 

 these papers in the Philosophical Magazine, vol. vi. Both these 

 gentlemen have examined this East India plant, its juice, and the 

 caoutchouc formed by it : and they concur in ascertaining its ana- 

 logy to the American production. Mr. Howison observes that the 

 milk runs but slowly from incisions in the bark, it being full em- 

 ployment for one person to collect a quart in two days. A much 

 more expeditious mode, but ruinous to the vine, is cutting it in 

 lengths of about two feet, and placing under both ends vessels to 

 receive the milk. The best is always procured from the oldest 

 vines ; and is often obtained in a consistence equal to thick cream, 

 and which will yield two-thirds of its own weight in caoutchouc. 

 The chemical properties of this milk were found strikingly to re- 

 semble those of animal milk. A number of other very curious par- 

 ticulars, which our limits will not permit us to insert, are detailed 

 in the interesting communications to which we have already re- 

 ferred. 



The chemical properties of caoutchouc, as far as they have been 

 ascertained, are principally as follow. It is softened by heat, and 

 at length melts, swelling up, and emitting an unpleasant odour : on 

 cooling again, it remains adhesive, acquires the consistence of tar, 

 and never recovers its former elasticity. It yields on distillation 



