RUBBER 711 



grave doubts whether the Mexican Indian is capable of 

 the delicate work required for tapping Heveas, or if 

 sufficient men can be obtained. That is the great trouble 

 with Castilloa cultivation in Mexico insufficient and 

 very inferior labour. If the women and girls could be 

 employed the tapping- of Heveas might be done ; but they 

 will not, or cannot, tap Castilloas, which, owing to the 

 original close planting, require i6-lt. ladders. 



Experimental Work carried out with a view to devising 

 Methods of Tapping to increase the Yield. 



Scores of experiments have been made with that object 

 in view, but the yield could only be increased by putting 

 more cuts on the trees. Ladders were lengthened from 

 12 to 1 6 ft., which would enable the tapper to reach 

 up to some 20 ft., the lowest cut being close to the roots. 

 Trees have been experimentally tapped monthly, six 

 times a year, and four times a year, but, as I have said, 

 they yielded no more than with two tappings per annum. 

 I am now satisfied that the yield can only be increased 

 by fostering the growth of the trees, by thinning out to 

 increase their leaf area, by forking, manuring, and 

 mulching that is, by cultivation. Spindly trees have 

 been pollarded, the result being fairly satisfactory. The 

 growth of other trees in measured areas is watched care- 

 fully, monthly measurements being taken and reported. 

 The result of forking and manuring these measured trees 

 has been most satisfactory, but the idea of increasing 

 the yield by new methods of tapping has been quite 

 abandoned. The maximum yield I look for is that of 

 the old cultivated trees at La Zacnalpa, 2 Ib. per tree, 

 and this can only be attained by painstaking cultivation. 



The Yield of Rubber from the different Varieties (or 

 Species) of Castilloa which occur in Mexico. 



I must say at once that I am not a botanist, and I have 

 only noted two different species of Castilloa in Mexico. 

 An eminent Washington botanist gave the Castilloas of 

 Soconusco (the district with which I am dealing) a distinct 

 name, Castillo (Castilloa) lactlflua, but in my opinion the 



