including the powdered seeds of the tree Anadenanthera colubrina, whose distribution - and its artistic depiction in later Andean cultures - makes it the most likely ingredient in the Chavin brew. Anadenanthera-snuffing has been largely replaced in many areas of the Amazon by ayahuasca-drinking, a more manageable technique of DMT ingestion, but this displacement is a recent one, and Anadenanthera is still used by some tribal groups in the remote forest around the borders of Peru, Colombia and Brazil. Even today, the tree grows up the Amazonian slopes of the eastern Andes and as far west as the highlands around Kotosh. The transformation offered at Chavin was, it seems, mediated by the combination of these two extremely potent psychedelics.The presence of these two plants at Chavin, without necessarily illuminating the purpose or content of the rituals, has certain implications. The effects and duration of San Pedro and Anadenanthera are very distinct from one another, and characterised by quite different ritual uses. San Pedro, boiled, stewed and drunk, can take an hour or more before the effects are felt; once they appear, they last for at least ten. The physical sensation is euphoric, languid, expansive, often with some accompanying nausea; in many Indian traditions, such effects are dealt with by setting the participants to slow, shuffling three-step dances and chants. The effect on consciousness is similarly fluid and oceanic, including visual trails and a heightened sense of presence: the swirling lines which surround the figures at Sechin could perhaps be read as visual representations of this sense of energy projecting itself from the body - particularly from the swirling, psychedelicised intestines - into an immanent spirit world.Anadenanthera, by contrast, is a short sharp shock, and one thats powerfully potentiated by a prior dose of San Pedro. About a gramme of powdered seed needs to be snuffed, enough to pack both nostrils. This process rapidly elicits a burning sensation, extreme nausea and often convulsive vomiting, the production of gouts of nasal mucus and perhaps half an hour of exquisite visions, often accompanied by physical contortions, growls and grimaces which are typically understood in Amazon cultures as feline transformations. Unlike San Pedro, which can be taken communally, the physical ordeal of Anadenanthera tends to make it a solitary one, the subject hunched in a ball, eyes closed, absorbed in an interior world. This interior world is perhaps recognisable in the new decorative elements which emerges at Chavin. Images like the spectacular glyph that covers the Raimundi stela - a human figure which seems to be flowering into other dimensions and sprouting an elaborate headdress of multiple eyes and fangs - are reminiscent not just of ayahuasca art in the Amazon today but also of the fractal, computer-generated visual work associated with DMT in modern Western subcultures.The distinct effects of these two drugs suggests a functional division between two elements or phases of the ritual which is mirrored in Chavins contrasting architectural elements. Like the kiva in Southwestern Native American architecture which it so closely resembles, the circular plaza is readily interpreted as a communal space,