COLLECTING THE LATEX. 89 



associated with the last-mentioned systems is certainly open to 

 serious criticism. In a large number of cases the whole of the 

 bark from this area has been excised away in one year. It is 

 perfectly unreasonable to expect that bark, one year old, will 

 yield rubber equal in quantity and quality to that produced by 

 the original bark. 



Latex is quickly renewed in the bark, but the production of 

 a good percentage of caoutchouc in the latex takes a much 

 longer time. As previously pointed out under the heading 

 " Latex," in one instance the percentage of water in the 

 latex, obtained from renewed bark, was 90 per cent., whereas 

 latex from the original bark contained only from 30 to 50 per 

 cent, of water. Obviously, then, planters should endeavour to 

 regulate their tapping operations in such a way that the old bark 

 is not pared away until the new bark with its contents is mature. 

 It should be borne in mind that the fusion of cells is going on 

 daily in the secondary cortex by the breaking down of transverse 

 walls, therefore the greater the age of the bark, under ordinary 

 conditions, the greater the number of laticifers. 



With due care an inch of bark need only be cut away after 

 from twenty to thirty parings have been made, so that it should 

 be possible to tap a given tree seventy-five times a year and still 

 take advantage of wound response. Excising the bark at this 

 rate, it would not be necessary to tap the renewed bark until it 

 was four years of age. 



Tapping is only carried out during one season in the Amazon, 

 and it is possible that, if tapping of cultivated trees were sus- 

 pended for several months, especially during the resting season, 

 better results would be obtained. 



COLLECTING VESSELS, &c. 



Vulcanite or aluminium vessels should be preferably used 

 for collecting and transporting the latex, to those manufactured 

 of iron and tin, as the latter become coated with rust with which 

 the rubber is liable to become contaminated. 



With a view to encourage the flow of latex down to the 

 collecting vessels and consequently lessen the production of scrap 

 rubber, the use of an invention known as the drip-tin has been 

 suggested. 



