ENVIRONMENT 81 



ment proved but the incentive to another at- 

 tempt. It is a vivid picture; the whole cactus 

 family in a death struggle for supremacy over 

 enemies which threaten its very existence - 

 millions and millions of the family perishing in 

 the struggle, and perhaps but one victorious sur- 

 vivor left to start a new and armored race. 



It is wonderful, but whenever we plant a 

 cactus slab to-day we see evidences of adapta- 

 bility even more wonderful than this. 



The slab of cactus is an olive green color as 

 we put it in the ground. It is flat, of an oval 

 shape, an inch or less in thickness. Its internal 

 structure is of a soft juicy texture like most 

 succulent vegetables largely water, 



As the slab sends down roots, it begins to pre- 

 pare itself to bear the burden of the other slabs 

 which are to grow above it. 



The thin, flat shape thickens out until it is 

 almost spherical; thus presenting a curved sur- 

 face in four directions instead of in two, it braces 

 itself against the winds which will endanger the 

 tender new slabs far above it. 



Its tender woody fibers grow tough and re- 

 sistant; it loses its velvety skin and develops a 

 bark like that of a tree. 



Within a year after planting, this cactus slab 

 will have changed in appearance and in char- 



