LUTHER BURBANK 
by ravenously hungry antelopes, we will say— 
antelopes which had increased in numbers year 
by year while their food supply year by year was 
relentlessly dwindling —of these million plants 
gnawed down to the roots, perhaps but a thousand 
or two had the stamina to throw out new leaves— 
and to try over again. 
But just as in its previous experience, the 
cactus had changed the character of its stalk, so 
now it undertook another change—the acquisition 
of an armor. 
This armor at first consisted of nothing but a 
soft protuberance, a modified fruit bud or leaf, 
perhaps, ineffectual in warding off the onslaughts 
of the hungry animals. 
So, of the thousand or two left out of the 
million, there may have been but a hundred which 
were able to ward off destruction. 
The hundred, stronger than the rest, though 
eaten to the ground, were able still to send up new 
leaves, and with each new crop the hairs became 
stiffer and longer, the protuberances harder and 
more pointed, until finally, if there were even only 
one surviving representative of the race, there was 
developed a cactus which was effectually armored 
against its every animal enemy. 
One such surviving cactus, as transformed 
throughout ages and ages of time, meeting new 
[18] 
