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for the future. There can be no doubt that were it not for the 
faraway climate required for the growth of rubber trees, the interest 
displayed by manufactures in the cultivation and exploitation of 
rubber trees would long ago have assumed a practical shape of the 
same kind as is shown by the manufactures of beet root sugar on 
the Continent, and which is responsible for much of the enormous 
development and success of that industry. 
Much has also been achieved in regard to the question as to 
which of the numerous rubber trees offer the best prospects for the 
purpose of methodical cultivation in different parts of the world, 
although it cannot be said that this important question has finally 
been settled in favour of one species or the other. 
But great uncertainty and much diversity of opinion still exists 
regarding the most satisfactory method of tapping the trees, col- 
lecting the latex, and, chief of all, concerning the most rational 
process of converting the latex into the most perfect form of com- 
mercial rubber. Indeed, we consider the most important prelim- 
inaries in the exploitation of a rubber district to consist (i) in the 
careful physiological examination of the tree, and (2) in the ex- 
haustive investigation of the chemical and physical problems arising 
in the coagulation of any given latex. Upon the first of these two 
points depends the fife of the trees under exploitation, upon the 
second the quality and market value of the rubber produced. 
Now while the first of these two points has in the past received 
a good deal of attention, the second is generally studiously neg- 
lected, or more or less perfunctorily enquired into, in saying 
this we are by no means unmindful of the valuable suggestions due 
to Biffen, and of the interesting results obtained by M. HARNET 
in the Soudan, but we are not aware that at present rubber exploita- 
tion companies have realised the necessity of investigating in a 
systematic manner and by the methods of modern chemical research 
the best conditions for the coagulation of the latex. 
Coagulation of Latex. 
We have often felt that there seems to be some sort of unex- 
pressed, but generally accepted notion that the mode of coagulation 
may affect the general purity of the rubber produced, its colour, 
percentage of occluded water, and general suitability, but that it 
has no influence upon the intrinsic quality of the india-rubber itself. 
In other words, it appears to be taken for granted that the india- 
rubber exists in the latex ot the tree as a substance identical with 
that of its commercial forms, as is, for instance, certainly true of 
the oils. We venture, therefore, to submit to the consideration of 
those interested in this subject the following points which we be- 
lieve to have an important bearing upon the quality of the rubber 
produced from a latex: — 
1. It is extremely doubtful, if not altogether improbable, that 
rubber as such does not pre-exist in the latex, but merely a sub- 
stance capable of agglomeration by polymerisation (coagulation)- 
2. This being conceded, and the results of a careful chemical 
and microscopical study of the latex leave very little room for doubt 
