CACTUS AND GREASE- WOOD 



131 



Perhaps now we are coming closer to an under- 

 standing of Nature's method. It is the species 

 that she designs to last, for a period at least ; 

 and the individual is of no great importance, 

 merely a sustaining factor, one among millions 

 requiring continual renewal. It is a small mat- 

 ter whether there are a thousand acres of grease- 

 wood more or less, but it is important that the 

 family be not extinguished. It grows readily 

 in the most barren spots, is very abundant and 

 very hardy, and hence is protected only by an 

 odor and a varnish. On the contrary take the 

 bisnaga a rather rare cactus. It has only a 

 thin, short tap-root, therefore it has an enor- 

 mous upper reservoir in which to store water, 

 and a most formidable armor of fish-hook 

 shaped spines that no beast or bird can pene- 

 trate. Remove the danger which threatens the 

 extinction of the family and immediately Nat- 

 ure removes the defensive armor. On the 

 desert, for instance, the yucca has a thorn like 

 a point of steel. Follow it from the desert in- 

 to the high tropical table-lands of Mexico where 

 there is plenty of soil and moisture, plenty of 

 chance for yuccas to thrive, and you will find 

 it turned into a tree, and the thorn merely a 

 dull blade-ending. Follow the sahuaro and the 



Preserva- 

 tion of the 

 species. 



Means of 

 preserva- 

 tion. 



