ON GUM AND SUGAR TREES 
right combination to produce organic substances. 
And, although this work is only at its beginning, a 
good measure of success has been attained. 
In particular, the chemists of Germany and 
England have recently succeeded in combining 
carbon and hydrogen in the proportion of 8 atoms 
of the former to 7 of the latter and thus have 
produced an artificial rubber that is not merely 
an imitation rubber but is as truly pure rubber as 
if it had been produced in the cellular system of 
a plant. 
Indeed, the artificial product may be said to be 
somewhat more pure than the natural, inasmuch 
as the latter is more or less contaminated by ex- 
traneous products. 
Reference has elsewhere been made to the 
familiar feat of the chemist through which the 
famous dyestuffs, indigo and madder, have been 
manufactured in the laboratory, and manufac- 
tured so cheaply as to compete successfully with 
the natural product of the indigo and madder 
plants. What was a large plant industry only a 
few years ago has thus ceased to have importance. 
The indigo plant is still cultivated in the east, but 
the entire industry has been changed by the dis- 
coveries of the chemist. 
Only a few years ago a plant known as the tar 
weed (Madia), to which we have had occasion to 
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