DESERT SCENES IN ZACATECAS 451 



ico. Two and a quarter millions of dollars' worth of this product came 

 from one district in one year recently and much more is following. 

 Back in the middle of the eighteenth century it was discovered that the 

 source of the rubber in the balls with which the Indians were wont to 

 amuse themselves, was this guayule. As the Indians formerly did, so 

 one now may extract this rubber in the same crude way by chewing the 

 bark and rejecting the fiber until sufficient gum for the purpose has 

 been accumulated. 



That this gum is a by-product in the physiological processes of the 

 plant and stored in its tissues in the form of granules, is not the least 

 of its interesting features, for most of the rubber-bearing plants 

 known to the public are trees yielding a milky fluid from which the 

 rubber is obtained by coagulation. But in this case the rubber is not 

 obtained by tapping, but by the immediate destruction of the plant. 



Besides the mesquite and the greasewood and other shrubs that 

 clothe the valleys and lower slopes, the steeper acclivities abound in 

 Jatropha, Buddleia, Salvia, Bahia, Ephedra and many other woody 

 plants, members of other genera to the number of a hundred or more, 

 are scattered among the agaves, the palmas and the cacti up and down 

 the mountainside. 



One who has not sought these plants where they grow can have 

 little idea of their number and variety, nor of their varied structural 

 and physiological attributes which make for complete fitness in the 

 stern environment of the desert. Here they grow and flourish where it 

 would seem there is no chance for life. But they thrive in these barren 

 wastes — league on league of plain and mountain, where there is neither 

 spring nor pool nor forest shade, blistering heat and glare above and 

 hot dry stones beneath, and find it sufficient. 



