276 FOREST LIFE AND SPORT IN INDIA 
and he has since compiled an able monograph which 
affords the fullest information on a subject that is 
becoming of considerable commercial importance in 
India, even though it is not likely that this par- 
ticular species will ever be extensively cultivated, 
for there are others that promise to provide a more 
remunerative investment. 
The importation of wild rubber from the terri- 
tories beyond Assam and Burma afforded at one 
time a considerable revenue to the British Govern- 
ment, but wasteful utilization has led to the usual 
result of shortening the supply ; and it seems certain 
that in the future plantation rubber will entirely 
control the world’s market, as it perhaps already 
does to a great extent. The Ficus elastica is a 
light-loving plant, and occurs naturally as an epi- 
phyte growing on the tallest forest trees, whose 
stems it encircles till the host is hidden and for- 
gotten. The enormous height of the wild tree 
therefore is due to the host selected, and is not 
apparent in an artificial plantation originating from 
seed or from cuttings; there the tree is forced to 
itself form a trunk for the support of its heavy 
crown ; it does not desire to do this, nor has it, when 
surrounded by stems of similar age, any special 
impulse towards height growth so long as it secures 
its due share of illumination. The tree has also in 
close-growing plantations little use for the develop- 
ment of aerial roots; but, on the other hand, the 
underground root system coalesces, so that no tree 
can be termed entirely independent. It is probably 
due to the unnatural position of the tree, and to 
neglect to force its upward growth in early youth, 
