220 THE CENTRAL AMERICAN RUBBER TREE 



thin cutting edge about 1^ in. wide. The incisions are 

 arranged in vertical rows about 4 in. apart, the distance 

 between the cuts in each row being about 12 in. ; the 

 tapping extends round the entu'e circumference of the 

 tree and is carried to a height of 6 ft. or more. The latex 

 runs down the stem and is collected in a calico apron 

 fixed round the base of the tree. 



The latex flows from the cuts for periods ranging from 

 twenty minutes to two hom-s, and no further yield is 

 obtained by reopenmg the incisions. The latter practice 

 has in fact been found to be fatal to CastiUoa trees. The 

 trees may be tapped any time during the year except in 

 the dry season, the length of which varies in the different 

 districts. At La Zacualpa the tapping period lasts for 

 ten months of the year, from April to January. 



Until recently, cultivated Castilloa trees were not 

 tapped in Mexico until they were seven years old, but it 

 has been found that four-year-old trees which have 

 attained a girth of 15 in. can be lightly tapped without 

 injury. The young trees are fu'st tapped to a height of 

 6 ft. only and the incisions are gradually carried higher 

 as the trunk increases in girth. Mature trees are tapped 

 three times a year. 



Preparation of the Rubber. — The rubber is prepared on 

 the plantations by the native method of coagulating the 

 latex with an infusion of the stems of the "Moon " vine, 

 or by alio whig the latex to cream, or by spinning it in 

 a centrifugal machme. 



Creaming. — Castilloa latex " creams " very readily 

 when diluted with water and allowed to stand, and this 

 behaviour aftords an easy method of preparing the rubber. 

 The latex is first strained by means of a centrifugal strainer, 

 and is then diluted with water and poured into settlmg 

 tanks. The diluted latex is allowed to stand until the 

 rubber globules have completely separated as a cream, 

 and the clear serum is then run off as completely as pos- 

 sible by means of a pipe at the bottom of the tank. The 

 cream is stirred up with a fresh supply of water and 

 allowed to stand again until complete separation has 

 occurred. This treatment may be repeated several tunes, 

 and finally the cream of rubber globules is separated 

 and made to coagulate either by pressm-e or by working 

 it with wooden paddles. The freshly coagulated rubber 



