( 4 ) 
that the scope for selection amongst the trees on 
our plantations is very wide. This latter fact is 
amply disclosed by a study of the accumulated mass 
of data regarding the variation of our populations 
of trees. Whatever method of plant improvement 
is applied to Hevea, it involves in the first place 
a choice of parent trees, which necessitates a 
systematic study of the variation between individual 
trees on a plantation. During the past seven years 
a considerable amount of investigation has been 
carried out in this connection in all Eastern rubber 
producing countries. 
Whitby, Cramer, and several others have published 
interesting and conclusive articles proving variation 
in Hevea in almost all its parts ; leaves, seeds, bark, 
branches, root systems, and in quality and quantity 
of rubber etc.; but we are concerned chiefly with 
dry rubber production. 
It remains to be proved by experiment that the 
variation is due to inherent differences, and not to 
accidental differences of environment, both present 
and past. 
The Botanical Division of the Department of Agri- 
culture has figures extending over two years, which 
show that the variation in latex production per 
alternate-daily tapping, from a population of ap- 
proximately 500 twenty-eight year old trees, ranges 
from practically nothing up to 15 ounces or from 
0 to 45 lbs. of dry rubber per tree per annum. 
Moreover, of this population, not less than 11 trees 
yield over 28 lbs. dry rubber per annum, with alter- 
nate day tapping on a V on half the tree, and in 
every case the cut was situated, during the entire 
tapping period, more than one foot above the base 
