OF PLANTS. 341 



interesting. The bread-fruit of the South Sea 

 Islands (Artocarpus incisd) is well known from the 

 descriptions of the voyagers ; and though its 

 qualities have been extolled far beyond what they 

 really deserve, it is a very interesting, and, in 

 those countries, a very useful tree. But as that 

 tree furnishes bread in one part of the world, trees 

 of the same family yield milk in others. There is 

 a sort of animal principle, not a principle of animal 

 life, but an affinity to animal matter in most of 

 the family. That is contained in the substance 

 called caoutchouc ; familiar to most people as " In- 

 dian rubber," remarkable alike for its elasticity, 

 its insolubility in water, and the difficulty with 

 which it can be cut. On these accounts it is now 

 extensively used in the arts, not only for its origi- 

 nal purpose of effacing black lead from paper, but 

 as an ingredient in varnishing, in making water- 

 proof cloth, shoes, and numerous other articles. 

 Though the whole family contain more or less of 

 that substance, there are many of them, such as 

 the mulberry and the common fig, in which the 

 quantity is so small that it is not worth extracting. 

 But although the substance is procured in great 

 quantities, the plants which yield the greatest 

 abundance are not very clearly determined. In- 

 deed, it should seem that the plants which pro- 

 duce the greater part of the caoutchouc of com- 

 merce, belong to other families. That of Sumatra, 

 and the other islands on the south-east of Asia, is 

 obtained from some species of Urceola. One of 

 them, the elastic, is very plentiful in Palo Penang, 

 or Prince of Wales' Island. It grows to about 

 the thickness of a man's arm, and is cylindrical, 

 with pale bark, very much cracked. It runs along 



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