132 



THE DESERT 



pitahaya into the tropics again, and with their 

 cousin, the organ cactus, you find them growing 

 a soft thorn that would hardly penetrate cloth- 

 ing. Abundance of soil and rain, abundance 

 of other vegetation for browsing animals, and 

 there is no longer need of protection. With 

 it the family would increase too rapidly. 



So it seems that Nature desires neither in- 

 crease nor decrease in the species. She wishes 

 to maintain the status quo. And for the sake 

 of keeping up the general healthfulness and 

 virility of her species she requires that there 

 shall be change in the component parts. Each 

 must suffer not a " sea change," but a chemical 

 change ; and passing into liquids, gases, or dusts, 

 still from the grave help on the universal plan. 

 So it is that though Nature dips each one of her 

 desert growths into the Styx to make them in- 

 vulnerable, yet ever she holds them by the heel 

 and leaves one point open to the destroying 

 arrow. 



Yet it is remarkable how Nature designs and 

 prepares the contest the struggle for life 

 that is continually going on in her world. How 

 wonderfully she arms both offence and defence ! 

 What grounds she chooses for the conflict ! 

 What stern conditions she lays down ! Given a 



