8 CONTENTS. 



Page. 



The culture of Castilla 48 



Shade in the culture of Castilla • 48 



Shade not a necessity 48 



Relative cost of shade culture 51 



Effect of shade on form of tree 51 



Shade and rubber production 52 



Leguminous shade trees to be preferred 54 



Distance between rubber trees 54 



Methods of clearing land for rubber planting 55 



Clean culture with forest protection 56 



Methods of handling Castilla seeds 56 



Seed beds and nurseries 58 



Propagation of Castilla from cuttings 59 



Castilla as a shade tree 60 



Extraction of the latex of Castilla 62 



Primitive methods of tapping 63 



Age at which planted trees may be tapped 64 



Direction and shape of incisions 66 



Tapping instruments 67 



Multiple tapping 68 



Protection against thieves 68 



Methods of coagulating the latex of Castilla 69 



Coagulation by creaming 69 



Discoloration of Castilla latex 71 



Other methods of coagulation , 72 



Coagulation of scrap rubber 73 



Productiveness of Castilla 74 



Yield of wild trees . 74 



Yield of cultivated trees 74 



Profits and prospects of Castilla culture 76 



Management of rubber plantations 76 



Security of investments in rubber plantations 78 



Requirements for successful rubber plantations 80 



Opinion of the United States consul-general in Mexico 83 



Concluding summary 84 



Description of plates 86 



