The most concentrated sap from the mavacure is not thick enough to stick on arrows. It is thus only to thicken the poison that another concentrated infusion of vegetable sap is added. This is an extremely sticky sap taken from a tree with long leaves called kiracaguero. As this tree grows a long way off, and at this period is without flowers or fruit like the bejuco de mavacure, we were not able to name it botanically. I have often spoken of the ill fate that prevents travelers from studying the most interesting plants. When you travel quickly you hardly see an eighth of the trees that offer the essential parts of their fructification, even in the Tropics where flowers last so long.

Having outlined the general aim, I will now briefly glance at the collections and observations we made. The maritime war during our stay in America made communications with Europe very uncertain and, in order for us to avoid losses, forced us to make three different collections. The first we sent to Spain and France, the second to the United States and England, and the third, the most considerable, remained constantly with us. Towards the end of our journey this last collection formed forty-two boxes containing a herbal of 6, equinoctial plants, seeds, shells and insects, and geological specimens from Chimborazo, New Granada and the banks of the Amazon, never seen in Europe before. After our journey up the Orinoco, we left a part of this collection in Cuba in order to pick it up on our return from Peru and Mexico. The rest followed us for five years along the Andes chain, across New Spain, from the Pacific shores to the West Indian seas. The carrying of these objects, and the minute care they required, created unbelievable difficulties, quite unknown in the wildest parts of Europe. Our progress was often held up by having to drag after us for five and six months at a time from twelve to twenty loaded mules, change these mules every eight to ten days, and oversee the Indians employed on these caravans. Often, to add new geological specimens to our collections, we had to throw away others collected long before. Such sacrifices were no less painful than what we lost through accidents. We learned too late that the warm humidity and the frequent falls of our mules prevented us from preserving our hastily prepared animal skins and the fish and reptiles in alcohol. I note these banal details to show that we had no means of bringing back many of the objects of zoological and comparative anatomical interest whose descriptions and drawings we have published. Despite these obstacles, and the expenses entailed, I was pleased that I had decided before leaving to send duplicates of all we had collected to Europe. It is worth repeating that in seas infested with pirates a traveler can only be sure of what he takes with him. Only a few duplicates that we sent from America were saved, most fell into the hands of people ignorant of the sciences. When a ship is held in a foreign port, boxes containing dried plants or stones are merely forgotten, and not sent on as indicated to scientific men. Our geological collections taken in the Pacific had a happier fate. We are for their safety to the generous work of Sir Joseph Banks, President of the Royal Society of London, who, in the middle of Europe's political turmoils, has struggled ceaselessly to consolidate the ties that unite scientific men of all nations.