We entered into the cave following the rivulet, some 28 to 30 feet wide. We walked along the banks as far as the calcareous incrustations allowed us; frequently, when the current slipped between high clusters of stalactites, we were forced to walk along the river bed, only 2 feet deep. To our surprise we learned that this underground stream is the source to the Caripe river and becomes navigable for canoes a few leagues from here, after joining the Santa Maria river. Along the underground rivulet banks we found a quantity of palm-tree wood, remains of trunks used by Indians to climb to the cave's ceiling when searching for nests. The rings formed from the traces of the leaf stems are used as a perpendicular ladder.

A dreadful circumstance forced us to stay a whole month in Angostura. The first days after our arrival we felt tired and weak, but completely healthy. Bonpland began to study the few plants that he had managed to protect from the humidity while I was busy determining the longitude and latitude of the capital and observing the dip of the magnetic needle. All our work was interrupted. On almost the same day we were struck by an illness that took the form of a malignant typhus in my travelling companion. At that time the air in Angostura was quite healthy and, as the only servant we had brought from Cumana showed the same symptoms, our generous hosts were sure that we had caught the typhus germs somewhere in the damp Casiquiare jungles. As our mulatto servant had been far more exposed to the intense rains, his illness developed with alarming speed. He got so weak that after eight days we thought he was dead. However, he had only fainted, and he later recovered. I too was attacked by a violent fever; I was given a mixture of honey and quinine from the Caroni river (Cortex angosturae), a medicine recommended by the Capuchin monks. My fever continued to rise, but vanished the following day. Bonpland's fever was more serious, and for weeks we worried about his health. Luckily be was strong enough to look after himself; and took medicines that suited him better than the Caroni river quinine. The fever continued and, as is usual in the Tropics, developed into dysentery. During his illness Bonpland maintained his strength of character and that calmness which never left him even in the most trying circumstances. I was tortured by premonitions. It was I who had chosen to go up-river; the danger to my companion seemed to be the fatal consequence of my rash choice.

If the independent Indians have almost disappeared over the last century in those areas north of the Orinoco, it must not be concluded that fewer Indians exist at present than in the time of the bishop of Chiapas, Bartolomeo de las Casas. I have already proved in my work on Mexico how mistaken it is to assume the destruction and diminution of Indians in the Spanish colonies, as Ulloa has written 'Es cosa constante irse disminuyendo por todas partes el numero de los Indios' (There is everywhere a constant decrease in the number of Indians). There are still more than 6 million copper-colored races in both Americas, and though countless tribes and languages have died out it is beyond discussion that within the Tropics, where civilization arrived with Columbus, the number of Indians has considerably increased. (61)

We left the Esmeralda mission on the 23rd of May. We were not exactly ill, but emaciated and weak thanks to the torment of mosquitoes, the bad food and the long journey on that narrow and damp pirogue. We did not go further up the Orinoco than the mouth of the Guapo; had we wanted to reach the Orinoco sources we would have gone beyond this point, but private travelers are not authorized to leave pacified areas. From the Guapo river to the Guaharibo cataract there are only 15 leagues. But the cataract is crossed by a liana bridge where Indians armed with bows and arrows stop whites from entering their lands. Up to the present time the Orinoco posed two distinct problems for geographers: its sources, and the nature of its communications with the Amazon. This latter was the aim of our journey.

We stopped to observe the howler monkeys, which move in lines across the intricate branches linking the jungle trees in packs of thirty and forty. While watching this new spectacle we met a group of Indians on their way to the Caripe mountains. They were completely naked, like most Indians in these lands. Behind them came the women, laden with heavy packs, while all the men and boys were armed with bows and arrows. They walked in silence, staring at the ground. We would have liked to ask them if the Santa Cruz mission, where we hoped to spend the night, was far off. We were exhausted, and thirsty. The heat was increasing as the storm approached, and we had not found any springs. As the Indians invariably answered si padre and no padre we thought they understood a little Spanish. In their eyes every white is a monk, a padre. In the missions the color of the skin characterizes the monk more than the color of his habit. When we asked those Indians if Santa Cruz was far off they answered si or no so arbitrarily that we could make no sense of their answers. This made us angry, for their smiles and gestures showed that they would have liked to direct us as the jungle became thicker and thicker. We had to leave them; our guides, who spoke the Chaima language, lagged behind as the loaded mules kept falling into ravines.

From the mouth of the Meta, the Orinoco seemed freer of shoals and rocks. We navigated in a canal 500 toises wide. The Indians stayed in the pirogue, rowing without towing or pushing it with their hands, tiring us with their wild screams. It was already dark when we found ourselves by the Raudal de Tabaje. The Indians did not want to risk crossing the cataract and so we spent the night on land on a site that was extremely uncomfortable, on a rock bench with a steep slope sheltering a cloud of bats in crevices. All night we heard the cries of jaguars. Our dog answered by howling back. The deafening noise of the Orinoco waterfalls contrasted with the thunder grumbling over the jungle.

In this part of the cavern the rivulet deposits blackish earth, a mixture of silex, clay and vegetable detritus. We walked in thick mud to a place where, to our shock, we discovered underground vegetation. The seeds that the birds bring into the grotto to feed to their chicks germinate wherever they fall on to earth covering the calcareous Incrustations. Blanched stalks with rudimentary leaves rose to some 2 feet. It was impossible to identify the plants as the absence of light had completely transformed their form, color and aspect. These traces of plant life in the dark struck the Indians, usually so stupid and difficult to impress. They examined the plants in a silence inspired by a place they fear. You could have said these pale, deformed, underground plants seemed like ghosts banished from the earth's surface. For me, however, they recalled one of the happiest days of my youth when during a long stay at the Freiberg mines I began my research into the effects of blanching plants.