the sum realised BEN too small to make it worth while to con- 
tinue — them 
The sub stance is rea cee distinguished from ‘‘ Balata ” 
(Mimusops) or ‘‘ Rubber” (Hevea, etc.) by becoming plastie on 
exposure dry to a temperature of about 100° F. (the actual tem- 
perature at which it becomes plastic depends chiefly on the relative 
proportions of gutta and resin) or by immersion in hot water. It 
is tough like Balata and Rubber, but has not the elasticity of 
either and is not so serviceable for manufactures or in situations 
exposed to light and air, becoming more or less brittle. Under 
water or in the dark it is said to preserve its original character 
almost indefinitely. 
Gutta Percha is one of the noted discoveries which marked the 
progress of the 19th century. The historical details (see the 
references below) are as remarkable as those of Para Rubber, 
sively found in shallow ravines where the soil is of a compact 
Trees may be t tapped vis about D tss ata re to to 
Burn-Murdoch (see Agric. Bull. Str. Sett. vii. i. Se t. 1908, p. 389). 
the rate of growth of forest trees 1n us Malay tates is in some 
pee 1:69 inches per annum or 42 years to reach a girth of 
ft. at 6 ft. from the ground, in others the rate of increase has 
varied Pies 3-20 or 24 in. in 7 years, the girth increment being 
greater as the crown of the tree reaches the light. According to 
Sérullas (l.c. p. 5) the = is not fully grown till 28 or = years 
. of age; when it commences to flower and so continues e two 
years; and when mature the trunk is about 3 ft. in ue ches 
at about 5 ft. from the ground, yielding under ordinary cireum- 
stances about one-third of a pound of sap. A tree sent out from 
