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THE POPULAR SCIENCE MONTHLY 



tissues, accompanied by the agglomeration of the contained rubber. 

 The methods of the chemist have suggested extraction by the use of 

 suitable solvents, the rubber being recovered by differential solution and 

 distillation of the solvents. Both these methods have been adapted to 

 the extraction of rubber from the plant which shall claim brief atten- 

 tion in what follows. 



I refer to the guayvle, a low, gray or greenish-gray shrub (Figs. 1 

 and 2). 



Fig. 1. A large and unusually symmetrical Guayule Plant. 



of limited distribution within the Chihuahuan desert, having the center 

 of its geographical area very near to the northern boundary of the state 

 of Zaeatecas, Mexico. The southern extension of this area lies some- 

 what below San Luis Potosi ; to the north it is found in the Big Bend 

 country of Texas; here are rather small amounts, and of low stature as 

 compared with the conditions farther to the south. The plant scarcely 

 invades the state of Sonora, and is found only in the western part of 

 Xuevo Leon. 



The chief interest attaching to its occurrence in Texas is the fact 

 that it was here first discovered by Dr. J. M. Bigelow "near Escondido 

 (Hidden) Creek." The party of the Mexican Boundary Survey, of 

 which Bigelow was a member, in all probability rested at the large 

 spring which forms the source of this creek, a camping-place for un- 

 counted generations of Indians before the days of the white man. 

 Here, on the McKenzie ranch, east of Fort Stockton, the writer also 



