THE CEARA RUBBER TREE 149 



Experiments have been made in Nyasaland and Uganda 

 to determine the effect of reopenmg the incisions by- 

 means of a parer or a parer and pricker, as in the case 

 of Para trees, and very promising results have been ob- 

 tained (see pp. 151-4). Great care is, however, rcquii-cd 

 in tappmg by this method to avoid injm-ing the cambium, 

 as the bark of Ceara trees is thinner than that of Para 

 trees. 



Johnson has introduced a modified form of herringbone 

 tapping based on his experiments with Ceara trees. The 

 outer barii is removed from one half of the tree to a height 

 of 6 ft. and a vertical channel is cut at one side of the 

 stripped area ; six transverse cuts, 1 ft. apart, and 

 the lowest 1 ft. from the ground, are then made over 

 the half of the trunk and the latex is collected. Four 

 days later six more lateral cuts are made between the 

 first series ; after four more days a third series of six 

 incisions is made in the alternate spaces between the 

 first two series ; and finally, four days later, six further 

 cuts are made in the remaining spaces. The tree is then 

 allowed to rest until the wounds have healed, when the 

 opposite side of the tree is treated m the same way, the 

 two halves being thus tapped alternately. Some results 

 obtamed by this method are given on p. 155. 



Long vertical cuts have also been used successfully 

 in Nyasaland for tapping Ceara trees, and this method 

 is stated to have given the best results in some experi- 

 ments conducted in Hawaii. The procedure adopted 

 in the latter case was to make a number of very shallow 

 vertical incisions 4 to 5 in. apart in the bark ; the next 

 day the initial cuts were deepened so as to liberate the 

 latex, and then the incisions were reopened, always on 

 the same side, every day diiring the tapping period. It 

 is stated that very good yields of latex were obtained 

 by tapping in this way, and that the bark healed rapidly 

 from the side of the cut which was not reopened. 



In Brazil cultivated Ceara trees are tapped by the same 

 methods as those employed for the wild trees (see p. 139). 



Coagulation of the Latex. — The latex of the Ceara tree 

 is very easUy coagulated. It is first strained to remove 

 all mechanical impurities and is then diluted with water 

 and allowed to stand for a few hours, or overnight, untU 

 complete coagulation has taken place. Sometimes the 



