eight years are necessary to elapse before they can be exploited 
anew. : 
No accord has so far been established as to the best methods 
of extraction to be employed for the different species of mani- 
coba, nor as to the period most appropriate, the duration of the 
tapping or the yield of the wild trees or planted trees of dif- 
ferent ages. : 
The system adopted for the natural manicgoba, consisting in 
the tapping of the subterranean organs, has been applied to culti- 
vated manicoba; the incisions are made in a transversal sense 
and have the form of a V with the angle more or Jess rounded. 
The latex is gathered in the ground, at the bottom of a small 
cavity, opened up on the occasion of the discovery of the parts 
destined to be tapped; as a rule the worker covers the bottom 
of the cavity with a coat of clay in powder, in order to pre- 
vent the penetration of the latex and its mixing with the sandy 
soil; the employment of tigelinhas is desirable or of pots of 
glazed clay, refractory to rust. 
The latex thickens during the day, forming a sort of flat 
ball or biscuit of rubber, which goes on augmenting as the 
tapping process is multiplied. At the end of a week the rubber 
which has been obtained, is gathered together and washed in 
cold water, with a view of eliminating the remains of the serum 
and other impurities. This method, although primitive, permits 
of the production of pure rubber. The trunks and branches 
of the manicgoba are also cut; however, such system occasions 
great inconvenience. The extensive flaws heal up with dif- 
ficulty, as the bark of the tree is relatively thin the lactiferous 
vessels are located in the deep layers; it is not a rare thing 
that the death of the tree is caused thereby or that the attack 
of rodent insects or mushrooms is thereby facilitated. It may 
be of importance to note, that the incisions made simultaneously 
on the trunk, the branches and the underground parts, speedily 
exhaust the manicobeiras; and so the system of an alternate 
cutting is preferable. 
The tappings are practiced during the first six months of the 
year.and-extend themselves over a period of from 50 to 60 days. 
Owing,to the lack of data, the average yield of production, which 
varies according to the age of the trees, cannot be determined, 
however, the average production of the planted manicobas may 
under reserve, be calculated to reach during the space of 60 days 
120, 180, 240, and 300 grammes per tree of 2, 3, 4 and 5 years 
respectively, in accordance with a calculation made by Dr. L. 
Zehnter. 
The actual cost price in the plantations does not exceed 1$500 
per kilo, and might be reduced through an improvement in the 
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