5i6 



BIOLOGY AND HUMAN LIFE 



acter, in a strict biological sense. He combined a plant having 

 pale yellow berries with one having large, black berries— the 

 Lawton blackberry. From the hybrids he obtained segregating 

 offspring, and from the latter he was able to fix the individuals 

 that combined lack of pigment with some other desirable 



Fig. 217. Spineless cactus {Opuntia) 



This variety was established by Luther Burbank through experimentation. It grows 

 in arid soil that is otherwise useless, and promises to become a valuable fodder for 

 horses and cattle. (From photograph lent by Mr. Burbank) 



qualities in a pure state. Another new "creation" of Luther 

 Burbank's is the spineless cactus, which is shown in Fig. 217. 

 Every year the experiment stations and the private gardens 

 of seed producers, nurserymen, and horticulturists offer us 

 "new" flowers, fruits, and vegetables. Those that have to be 

 grown from seeds every year are the result of careful experi- 

 ments designed to discover the segregated individuals that have 

 the desired or usable combinations of characters. Those that 



