CHAPTER 1. 

 HISTORICAL ACCOUNT. 



Since about the middle of the last century, after the epoch-making 

 discovery of Charles Goodyear was made, the demand for crude rubber 

 has been steadily increasing. This demand was for a long period satis- 

 fied by the products harvested from the tropical forests of the Old 

 and New Worlds by natives whose methods are resulting in a gradual 

 depletion of the natural supply. This, in turn, has stimulated research 

 in three directions : toward obtaining a synthetic rubber, the ambition 

 of the chemist; toward discovering other rubber-producing plants, for 

 which search has been made into the farthest reaches of the tropical 

 forests of the world; and, finally, in the direction of the culture of the 

 various plants which before had been, in their feral condition, the source 

 of the much-desired material. Whatever the promise of the chemist 

 may be, there appears to be no abatement of interest at present in the 

 culture of those better-known trees which have been found to adapt 

 themselves to the hand of man, or in the discovery of hitherto unknown 

 rubber plants. Each new announcement, however vague the authority 

 may be, that a new rubber plant has been found, is hailed with precipi- 

 tous interest; and one that is well founded is soon followed by a period 

 of exploitation scarcely less fevered than on the finding of new gold- 

 bearing fields. When, a very few years ago, it became more generally 

 known that the plant commonly known as the guayule, and containing 

 an economically valuable amount of rubber, grew in abundance in the 

 desert country of northern Mexico, the vegetation of the adjacent arid 

 areas underwent minute examination in the hope of finding either this 

 or other similarly valuable plants, and even at the present moment the 

 excitement has not died away. 



The mere fact, however, that a plant indigenous to the desert 

 should be found to be of enough value to set in motion large business 

 operations involving millions of capital, based on the amount of the 

 raw material in sight, is sufficient to awaken definite interest. The 

 economic value of the desert is changed, and possibilities for the devel- 

 opment of wealth in a supposedly barren country take on new dimen- 

 sions. This has occurred, in point of fact, as a direct result of the dis- 

 covery that the plant guayule produces in the neighborhood of 10 per 

 cent of its weight of "bone-dry" marketable rubber. With the eco- 

 nomic history, bionomics, structure, and micro-chemistry of this plant the 

 present essay has to deal. 



ORIGINAL DISCOVERY AND DESCRIPTION. 



The guayule was first discovered by J. M. Bigelow, M.D., in 1852, 

 while attached to the Mexican Boundary Survey, " near Escondido Creek, 

 Texas." It was first described by Professor Asa Gray some years later. 

 His original description was based upon the type specimen, which is now 



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