404 
a period of about equal length is allowed to elapse without 
tapping. On others and the majority of places tapping is 
continued without cessation, in some cases trees having 
without any reduction of yield been tapped for 3| to 4 years 
every other day without cessation. On the question of 
daily or alternate days’ tapping planters are also divided, 
and experience of yields points somewhat to the advantage 
of the latter practice. 
There is no physiological reason why the tapping 
should cease during the leafless or fruit-bearing period ; the 
cutting of the small portions of the bark which tapping 
implies being in the case of a tree of 20" or more in girth 
so slight an injury as to be negligible. 
The best and simplest criterion for deciding how long 
to continue tapping is found in keeping a record of the 
amount of latex from each tree from 1,000 trees or from a 
field. If these figures show no serious and continuous de- 
cline there is no reason to stop tapping. On the other hand 
when, after a series of tappings, say 40 or 50, the amount of 
latex obtained decreases in a marked manner and this 
decrease is constant, the yields being less and less, then it is 
advisable to stop for a period of a month at least, and not 
to begin again until by an experimental .tapping it is found 
that the flow is again large. 
On one estate the tapping for a number of cuts was 
habitually stopped when the yield had attained the maxi- 
mum, and after some weeks tapping again produced less 
yield which increased fill the arbitrary time of ceasing. 
The method, which is adopted to a great extent from fear of 
using too much bark, is most unprofitable as it leads to 
stopping before the best yields have been obtained. 
It is naturally wise to so arrange tapping operations 
that it will not be necessary to retap renewed bark for some 
considerable period, but we do not yet know by experiment 
in the Malay States what length of time is necessary for a 
healthy tree, carefully tapped, to produce new bark contain- 
ing a large number of well-filled latex vessels. The time 
of four years has been arbitrarily fixed by some planters 
and their tapping schemes are arranged in relation to that 
period. That four years, three years, or twp years are 
necessary for the formation of bark suitable for tapping 
cannot yet be definitely stated, but it is highly probable 
from isolated cases where such experiments have been made 
that four years is unnecessarily long. 
