During the last several years we have witnessed the birth of new perspectives related to the study of collecting and museums, new insights that allow transcending the traditional institutional histories. Here, we analyze the build up process of a specific South American collection of the Ethnographic Museum of Neuchâtel seeking to highlight the relevant role of the vocational scientists and show how an accidental experience became a scientific discourse with a museographic effect. We intend to discuss the limitations associated with the intended construction of the scientific knowledge at the museum institutions and to reveal the flaws of the supposed anthropological truths kept within its walls.