ON GUM AND SUGAR TREES 
loid deposited in their bark. And doubtless the 
same thing is true of most or all other producers 
of commercial alkaloids.. 
Seemingly there is a splendid field, then, for the 
plant experimenter, could he establish a labora- 
tory and experiment garden in the tropics, in the 
development of improved races of cinchona trees 
and of numerous other suppliers of medicinal 
alkaloids, The monetary return from such an 
enterprise would probably be larger than that 
which usually rewards the efforts of the plant 
developer in temperate zones, because the field is 
virgin, and because there is no present possibility 
of competition outside the tropics. 
It remains to be said that there are a few other 
trees and shrubs of our own latitude that may 
advantageously command the attention of the 
plant developer for the improvement of quantity 
or quality of the by-products of their life activities 
that man has found useful. 
It seems not unlikely that the horse chestnut, 
or buckeye, could be so educated as to become a 
profitable starch producer. At present this tree 
produces an abundant crop of nuts, but these are 
worthless because they contain a bitter principle 
that makes them inedible. Yet the nut of the horse 
chestnut is very starchy and if the bitter principle 
could be eliminated there is no reason why it 
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