CAOUTCHOUC OB INDIABUBBER (Para). 
recently described, many of which are constructed so as to 
avoid wasteful excision of the cortical tissues or penetration 
to the cambium. The incisions may take the form of single 
oblique’cuts, V-shaped incisions, the half or full herring-bone, 
or the half or full spiral; the latter methods have come into 
prominence during the last year. Before incisions are made 
the areas to be tapped are cleaned and carefully defined. 
During collecting operations various appliances and chemicals 
are in use to aid the flow of the latex and prevent the closing 
of the latex tubes until they are more or less empty, and though 
good results have already been obtained, the methods of col¬ 
lecting the latex over large acreages are likely to be greatly 
improved in the near future. The trees are usually tapped 
from the base up to six or ten feet; large trees can be tapped 
to a much greater height. The latex usually increases up to 
the 3rd or even the 14th tapping ; Parkin’s results show a rise 
in yield from 61 c.c. for the first tapping to 449 c.c. for the 14th 
tapping. The rubber prepared from latex obtained from 
different levels of thirty-year-old trees, from the base to fifty 
feet, is quite good, but high tapping is not anticipated for 
the rubber trees which are now being planted. 
The trees are tapped according to size or age. In the Ama¬ 
zon district the Para rubber trees are said to require 15 years 
to come to tapping maturity in open plantations and 25 years 
m the forest, and in Para the trees are sometimes tapped for the 
first time when they have a circumference of 18 to 24 inches. 
The rubber obtained from Para rubber trees two, four, six, 
eignt, ten-twelve, and thirty years old does not differ con¬ 
spicuously in chemical composition, though the samples from 
the young trees usually show a tendency to become sticky and 
“ g<>0d qnalities - most countries the age of the 
trees when they can first be tapped is of minor importance, 
and a circumference of 20 to 24 inches, a yard from the ground, 
is commonly accepted as a safe size when the trees may be 
tapped for the first time. Tapping is usually done in the early 
morning and evening when the temperature is low, and is 
