It's the discovery of a society that probably doesn't exist today. Seeing that film, and many other auteurs-documentaries made half a century ago is the proof of the power of cinema because films like that are immortal. It's really powerful to go inside a culture like that and discover the intense ceremonies that are part of a cult influenced by the colonial oppression but still is able to survive with rituals.
Live document of a foregone era, precious witness of an extraordinary ritual, to the regular bystander this is nothing more than a cacophonic account of a bizarre cult, one that is so detached from what we can possibly comprehend that every effort we make is certainly in vain. The pace of the film, the speed of the words, the fragmented editing, a cocktail for confusion.
Probably Jean Rouch's most well known ethnographic film. The camera is used as an empirical tool to film a ritual possession and its theatrical interactive frame. This is not a work of art. The document is well detailed and descriptive but there is not much to say. Similar work but sligthly more inspiring and more elaborated can be found in Maya Deren's Divine Horesemen.