CHAPTER IX 
THE THORNLESS EDIBLE CACTUS 
Ape problems which confront Mr. Bur- 
bank in his work are many and some- 
times of great difficulty. One plant may 
present a simple nature and a comparatively 
short life history. Another may be exceed- 
ingly complex in nature and of great age. The 
first he finds easy of manipulation, the second 
often very difficult. The plants with millions 
of years back of them, which may be traced in 
the very rocks themselves, are likely to prove 
stubborn, to persist in their old habits; or, if 
they at first appear to yield, to return to these 
old habits at a later day. 
He has found this particularly true of the 
cactus, in the changing of which he has 
accomplished one of his most wonderful 
achievements. For years he had had the 
cactus under consideration. It had long 
seemed to him that it should be taken out of 
its environment and set forward among the 
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