Jan. I, 1898 .] 
rHE TROPICAL AGRICULTURIST. 
453 
“ The present process of producing Gutta-percha 
is, as has already been indicated, ■wasteful in the 
extreme, and very costly. The trees are either ringed, 
so as to cause a flow of sap, or felled, and in either 
case the tree is destroyed. Moreover the gum is 
mixed with impurities of vegetaL'le matter, such as 
pieces of bark, and even with mineral matter, like 
sand and earth ; to say nothing of the adulterations 
fraudulently added by the Chinese merchants. This 
necessitates a costly purification, which is achieved 
by softening and kneading the gum, or by squeezing 
it through wire gause or some similar process, the 
results of which are, at the best, not very satisfac- 
tory. Solution in bisulphide of carbon, or in benzine, 
has also been tried as a means of removing these 
impurities, but the quality is thereby deteriorated. 
After the impurities h-ave been mechanically removed, 
the gum is rolled between grooved or spiral rollers 
to expel water and air.” 
“ The yield from a single tree, too, is by no means 
great. A tree of fifteen to twenty years old gives 
only three to three and three-quarter ozs. of Gutta, 
one of thirty years old gives some nine ozs., 
according to Serullas ; and Burck gives about ten 
ozs. as the yield of a diohopsis tree twenty-six years 
old.” 
‘‘ The juice as it flows from the tree is "vyhite, 
on standing, it solidifies spontaneously, forming a 
sort of pellicle on the surface. On boiling or heating 
the juice, the Gutta collects into a more or less 
coherent lump.” 
” The Gut. a as it comes into the market has usually 
a brown colour, which, however, does not belong to 
the pure gum, but is due to a trace of colouring 
derived from the bai'k ; in some specimens the colour 
is dirty-white or pinkish, but the pure gum is really 
colourless. After being kept in the air for some time, 
the gum changes spontaneously to a brittle resin ; 
this change does not occur if light be excluded, nor 
is the gum changed by light if air be excluded. 
Under water it is quite stable, whether the water 
be fresh or salt. It is found, too, that specimens 
differ in their power of withstanding the action of 
the air, and it is believed that the purer the Gutta 
the better it will resist the action of the air. It 
is found, indeed, that pure Gutta is only slightly 
attacked even after a very long exposure to light 
and air.” . 
“ In what is usually termed “Gutta percha ” three 
distinct chemical substances are to be found. On 
boiling the gum with absolute alcohol a quantity of 
resinous matter is dissolved, varying with the speci- 
men of Gutta employed. Even the purest gum in 
the market yields some 18 to 20 per cent, of its 
weight to boiling alcohol ; and only what is left can 
be considered to be the chemically pure compound. 
Of worse vatieties of gum, 40 or even 50 per cent, 
may be thus dissolved. These dissolved resins, al- 
though possessed of good insulating properties, cause 
the Gutta to deteriorate very rapidly if they a,re 
present in large amount ; it becomes friable and easily 
disintegrated owing to oxidation. It is their pi’eseuce 
in poor qualities of Gutta which renders them un- 
suitable for telegraphic purposes. But up to 18 or 
20 per cent, they do not appear to act injuriously. 
The resins are named “ albane ” and “fluavile” 
respectively ; the former, when quite pure, forms 
white crystals, the latter is a yellow gum. Both appear 
to be products of oxidation of the pure Gutta, albane 
containing twice as much oxygen as fluavile. Oude- 
maus gives the formula of albane as C 20 H 22 O 2 , ^od 
that of fluavile as CjpIIjiO. But the chemical 
nature of these bodies, including Gutta-percha, has 
hardly been explored.” 
“ M. Serullas has been led to devise a method of 
extracting tliese mixed gums from the leaves, instead 
of from the trunk of the Isonandra Gutta-percha. 
This tree used formerly to flourish in the Malay 
Peninsula in the neighbourhood of Singapore, but 
until it was re-discovered in 1887 by M. Serullas, it 
had not been utilised as a source of Gutta for 
thirty years, and it was supposed to have become 
extinct. It is the product of this tree which M, 
Serullas says is best adapted for telegraphic purposes, 
for it yields gums containing the highest percentage 
of pure Gutta, mixed with the smallest proportion 
of albane and fluavile.” 
“ In the best Gutta, the following are the propor- 
tions of these constituents ; — 
Pure Gutta-percha.. .. 75 to 82 per cent 
Albane 19 ,, 14 „ 
Fluavile A ,, 4 ,, 
“ The process of extracting Gutta-percha from the 
leaves is an exceedingly advantageous one. To quote 
from the Sarawah Gazette, of the month of April, 
1895 : — “ A tree of twenty-five to thirty years old 
yields one catty (one and one-third lb.) of pure dry 
Gutta, the same amount can be obtained by two 
pluckings of the leaves.” The Gazette goes on to say 
that the stumps of trees which have previously been 
felled have now become covered with shoots, bear- 
ing rich crops of leaves ; and that M. Hourant has 
induced the natives to collect these leaves, and that 
they are now exported iir considerable quantity.” 
“ M. Serullas states that a tree thirty years old 
yields 25 to 30 kilograms (55 to 6(3 lb.) of green 
leaves, or about 11 kilograms of dried leaves (24 lb.), 
from which it is possible to extract, by methods to 
be described, no less than 1,000 to 1,100 grams (over 
2 lb.) of Gutta-percha, while the felled tree yields 
only 365 grams as a maximum. It would thus re- 
quire that a tree should yield only 7 kilograms of 
fresh leaves per annum in order to give as large a 
supply as the whole tree felled, aird with much less 
expenditure of labour.” 
“ It now remains to describe the method of extract- 
ing the Gutta-percha from the leaves. The process 
is due to M. Serullas. 
“The leaves, either fresh or dry, contain Gutta- 
percha. The process of drying, whether artifial or 
natural makes no difference to the percentage of 
Gutta, if the latter be reckoned on the dry leaves. 
The leaves, after being dried, are ground to a flue 
powder, and then mixed with one-teuth of their weight 
of caustic soda dissolved in water, and heated to 
boiling, or indeed digested under a slightly increased 
pressure. The liquor turns dark brown in colour, 
owing to the solution ol a brown colouring matter’ 
to which the Gutta-percha which usually comes into’ 
commerce owes its colour. The weight of the leaves 
and also their bulk, is materially decreased by this 
process. The power is then dried by heating to 
212°F. ; a solvent is added, in a closed vessel, so as 
to hinder loss by evaporation. The mixture is heated 
so as to effect the solution of the Gutta-percha more 
quickly. The mixture is placed in a filter press, 
and the solvent is separated as completely as possi- 
ble. The residue of leaves is washed vvith fresh 
solvent so as to extract the whole of the Gu»-ta. 
The solution is of a greenish-brown colour, owing 
to the solvent dissolving out some chloro’phyll 
the colouring matter of leaves. As some solvent 
remains adhering to the powdered leaves, a current 
of steam is driven through this residue, which carries 
off the solvent aud permits of its recovery. The 
extract is next placed in a still, and the solvent is 
partly removed by distillation, the pressure being 
somewhat reduced, so as to cause its boil at a tem- 
perature lower than that of boiling water. The 
concentrated extract is then run into a tank and 
mixed with twice its bulk of a volatile liquid. On 
mixing this liquid, which is done in a closed tank, 
there is produced a flaky or “ raggy ” precipitate of 
Gutta-percha. This precipitate is filtered off ao-ain 
by means of a filter press and the mixed liquids 
are run into a retort where they are submitted to 
distillation and are thus separated. 
“The cakes of Gutta-percha from the filter-press 
are dried at a low temperature ; they are then heated 
so as to soften them, aud in presence of water they 
are moulded into lumps.” 
“ The process is thus seen to be a very simple 
one. The products are easily prepared, and there is 
no loss except the unavoidable one, which always 
occurs when any substance is put through a round, 
and which is unlikely to be considerable.” ' 
