The thickening process takes place in rectangular holes of 1 metre long and half a metre broad, whose clayey sides are well paved and into them the latex is poured, care being taken that it is then covered up with palm leaves to prevent the entry of rain water. They thus obtain the caucho planks (rubber in cakes), which arrive in the market full of impurities, that depreciate its value very much and it is not at all a rare thing that water exists in cavities in the interior of it, thereby increasing the weight and making the transport dearer. The portions of the latex which flow out along the length of the trunk or fall into the cavities after that the cups have been taken away, thicken itself freely and form the “sernamby” of caucho, to-day much appreciated in the rubber markets, because of its being purer and not offering errors in weight. Each adult tree furnishes on the average from 50 to 56 litres of latex or in other words nearly 30 kilos of rubber. Each cake of the size above mentioned weighs nearly 60 kilos; it is thus necessary to cut down three trees so as to obtain one cake. The trees cut down sprout and commence to grow again, but 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 maniçoba, nor as to the period most appropriate, the duration of the tapping or the yield of the wild trees or planted trees of different ages. The system adopted for the natural maniçoba, consisting in the tapping of the subterranean organs, has been applied to cultivated maniçoba; the incisions are made in a transversal sense and have the form of a V with the angle more or less 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 prevent 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.