In presenting to the public the results of my journey through the lands about the upper waters of the Amazon, I make no pretence of challenging conclusions drawn by such experienced scientists as Charles Waterton, Alfred Russel Wallace, Richard Spruce, and Henry Walter Bates, nor to compete with the indefatigable industry of those recent explorers Dr. Koch-Grünberg and Dr. Hamilton Rice.

Some months of the years 1908 and 1909 were passed by me travelling in regions between the River Issa and the River Apaporis where white men had scarcely penetrated previously. In the remoter parts of these districts the tribes of nomad Indians are frankly cannibal on occasion, and provide us with evidence of a condition of savagery that can hardly be found elsewhere in the world of the twentieth century. It will be noted that this area includes the Putumayo District.

With regard to the references in footnotes and appendices, I have inserted them to suggest where similarities of culture or variations of a given custom are to be found. These notes may be of some use to the student of such problems as the question of cultural contact with Pacific peoples, and at the least they represent the evidence on which I have based my own conclusions.