Febkuarv 1, 1919.] 



THE INDIA RUBBER WORLD 



245 



year. The rest of the time it existed, did not grow, nor do any- 

 thing but sleep. Now, it is exceedingly difficult to get tree, shrub, 

 or plants to do anything that they and their forebears have not 

 previously done. They are hidebound in their prejudices, rock- 

 ribbed as to their habits. They have no ambition to speed up, 

 to be efficient, to be different. These plant prejudices must first 

 be understood and habits broken by coaxing, cajoling and fooling. 

 For example, the guayule habit of a slight growth in the spring 

 once a year was noted by the plant physiologist, who took ad- 

 vantage of it in this way. He furnished a simulated spring and 

 the guayule responded, then before it could settle back for months 

 of rest, another spring was sprung. If done at the exact psycho- 

 logical moment the plant responds. Again and again was this 

 done, and the plant, having no method of checking up its rapidly 

 recurring seasons, attained a lusty growth in record time. By 

 this method the fifteen-year development that the shrub was 

 accustomed to, and that it prefers, was accomplished in four 

 years. 



VARIETIES OF SHRUBS. 



One of the very interesting preliminaries in guayule cultiva- 

 tion was the study of varieties. To the average guayule expert 

 there were but two types of plants, the Parthenium Argentatum 

 which is the rubber producer, and the Mariola, Parthenium 

 Icanum, which much resembles it but contains no rubber. From 

 the beginning, the botanists began to segregate the rubber-pro- 

 ducing species into a great variety of types. The new species, 

 the Parthenium Lloydii, named after Professor Francis E. Lloyd, 

 is one of these varieties, characterized by differences in leaf, 

 flower, root growth, rubber content, etc., etc. Dr. McCallum, 

 in whose desert laboratory the most of this work was done, pub- 

 lished a statement in "Science" long ago that he had found 125 

 different species. ' He told the writer that his records showed to 

 date more than 900 different guayule growths and that the list 

 was still growing. 



THE RUBBER CONTENT. 



From the beginning of the experiments much care was taken 

 in the analysis of thousands of shrubs to learn all that could be 



over. The facts tabulated showed that there was a wide differ- 

 ence in the amount of rubber in the different shrubs. This ran 

 from one per cent to ten per cent to twenty per cent, and in rare 

 cases to twenty-seven per cent. Manifestly seed from the one 

 per cent would not pay to collect, much less to plant. The poorer 

 qualities were therefore thrown out and plants that were big pro- 

 ducers were selected as seed bearers for the future cultivated 

 shrub. 



QUALITY INVESTIGATION. 



Guayule rubber has not been considered to be of the highest 

 grade. When it first came upon the market its resin content was 

 so high and it was so soft that it was accepted with reluctance. 

 Indeed certain importers for years refused to allow that it was 

 rubber at all and scornfully dubbed it a substitute. In time, how- 

 ever, by new methods of extraction, and by deresination, it came 

 into its own as a valuable crude rubber and was used by the 

 millions of pounds. 



The searchers for guayule secrets, when they began to test the 

 quality of the rubber in different plants, learned some more sur- 

 prising truths. Some of the shrubs gave simply a black resinous 

 paste that contained not enough rubber for extraction. Others 

 contained rubber with say twenty per cent of resin, the type that 

 the whole trade is familiar with. A few, however, yielded a firm 

 hard product, low in resin and showing to a remarkable degree 

 the "nerve" that is so characteristic of the best crude rubber. 



The result was, of course, that the best producers were planted 

 as seed bearers for cultivated guayule. 



Xor was that all. By hybridization, that is the wedding of the 

 big producers with the best producers, plants were produced that 

 had the good qualities of each. Therefore with a big, best pro- 

 ducing seed stock the real cultivation of guayule was well on 

 the way toward success. 



SOLVING THE LABOR PROBLEM. 



In an age when almost everything is done by machinery, the 

 grovv'ing of india rubber, particularly the tapping and gathering, 

 is hand work entirely. Without vast gangs of coolies the pro- 

 duction of rubber in any considerable amount seems impossible. 



.A/J^^-J'-J^-tl tt^ ' 



learned concerning the rubber content in them. First of all, the 

 portions of the plants containing rubber were catalogd. This 

 was important in determining whether it was wiser to uproot the 

 plant for the sake of the rubber in the roots or to cut it off 

 above the roots, leaving them to produce new growths. With 

 cultivation in sight, however, there was much more to be learned 

 than the portion of the plant richest in rubber. That was 

 whether the ten per cent of rubber, the rough estimate of the 

 whole rubber content, was at all variable. The results of the 

 analyses were so astounding that they were done several times 



•LTivATED Guayule. 



With the cultivation and collection of guayule rubber, however, 

 machinery takes the place of men, and in almost every part of 

 the work. The preparation of the fields is done by disk harrovrs 

 drawn by tractors. The planting by specially built machines, 

 similar to tobacco planters that plow four furrows, set the plants 

 at the proper intervals, cover them in and pack the earth about 

 the roots. One machine plants eighteen acres a day. The culti- 

 vating is also done by machinery. For gatlnering there are two 

 systems; one cutting the rows down by a ha vesting machine, the 

 other plowing the plant out root and all, as 'n the harvesting of 



