The chemical operation, whose importance is exaggerated by the master of the curare, seemed to us very simple. The bejuco used to make the poison in Esmeralda has the same name as in the Javita jungles. It is the bejuco de mavacure, which is found in abundance east of the mission on the left bank of the Orinoco. Although the bundles of bejuco that we found in the Indian's hut were stripped of leaves, there was no doubt that they came from the same plant of the Strychnos genus that we examined in the Pimichin jungles. They use either fresh mavacure or mavacure that has been dried for several weeks. The sap of a recently cut liana is not considered as poisonous; perhaps it only really works when it is very concentrated. The bark and part of the sapwood contain this terrible poison. With a knife they grate some mavacure branches; the bark is crushed and reduced to thin filaments with a stone like those used to make cassava flour. The poisonous sap is yellow, so all this matter takes on that color. It is thrown into a funnel some 9 inches high and 4 inches wide. Of all the instruments in the Indian's laboratory, this funnel is the one he was most proud of. He several times asked if por alla (over there, in Europe) we had seen anything comparable to his embudo. It was a banana leaf rolled into a trumpet shape, and placed into another rolled trumpet made of palm leaves; this apparatus was held up by a scaffolding made of palm-leaf stalks. You begin by making a cold infusion, pouring water on the fibrous matter that is the crushed bark of the mavacure. A yellow water filters through the leafy funnel, drop by drop. This filtered water is the poisonous liquid; but it becomes strong only when concentrated through evaporation, like molasses, in wide clay vessels. Every now and then the Indian asked us to taste the liquid. From its bitterness you judge whether the heated liquid has gone far enough. There is nothing dangerous about this as curare only poisons when it comes into contact with blood. The steam rising from the boiler is not noxious, whatever the Orinoco missionaries might say.