22 
the occasional heavy yields from individual trees and suggest that 
such yields may be due to disease, especially canker, which, 
according to Mr. Marsden, in the early stages of attack stimulates 
the latex flow. In any series of experiments it is therefore neces- 
sary to examine the trees carefully to see that they are healthy. 
(2) It being admitted that a variation exists to determine how a 
classification of good and poor milkers can be made, Mr. Marsden 
states that good milking trees are known, but that for strict work 
it would be best to take the quantity and quality of latex figures 
for at least a year. It is certain that planters believe they can 
distinguish between good and poor milkers as on this depends 
the selection of trees in thinnin out. Mr. Marsden states that 
good milkers are characterised by “‘(1) fewness of seed pods, 
and (2) late wintering.’’ If this be so, there would appear to 
exist the same relationship between yields of rubber and seed: in 
Hevea as has been found to exist between yields of alkaloid and 
seed in Cinchona, and the same conclusion must apply, that is to 
say, with the present haphazard system there will be a tendency 
for the rubber-yielding capacity of the tree to diminish, but that 
by careful seed selection, it should be possible to raise the rubber- 
ee ie capacity considerably above the present average level. 
refers to trees with a smooth bark of a i 
: tches. 
(3) The collection of seeds from rele trees. Mr. Mar sden 
ith further reference to the question of seed selection Mr. 
Reeve has written the following report on the two points raised, 
i.e.— 
(4) To avoid cross-fertilisation. 
(5) Assuming that both male and female elements be derived 
from good milkers, there would probably be poor milkers 
among the ancestry. This would produce throw-backs in accord- 
ance with Mendel’s law which might necessitate selection over 
another generation. 
