The Indians of the Colombian Amazon take this dry 
powder into the mouth and, with the tongue, slowly 
work the gradually moistening mass until it is packed 
between the cheek and the gums. The slow ‘“‘dissolving”’ 
and swallowing of the coca-ash mixture induces the de- 
sired narcotic effects and, in many ways, is much pleas- 
anter and more satisfactory than the highland method of 
chewing harsh, dried leaves with lime pebbles or other 
alkaline agents. 
For many years, I had studied the preparation and 
use of coca in eastern Colombia and had experimented 
with it myself over long periods. The similarity of its 
preparation over such a wide area was rather monoto- 
nous. In March 1952, however, I encountered the only 
major difference in coca-making which ever came to my 
attention during my more than a decade of travel through 
the region. It was as unexpected as it was novel. Even 
Koch-Griinberg, whose ethnological work in the region 
is classic, fails to report this method of coca preparation 
(Koch-Griinberg, Theodor: ‘‘Zwei Jahre unter den 
Indianern’’ 1 (1909); 2 (1910). Neither does the most 
recent and most thorough study of coca in Colombia 
(Uscategui Mendoza, Nestor: ‘‘Contribuci6n al estudio 
de la masticacién de las hojas de coca’’ in Rev. Col. 
Anthrop. 8 (1954) 209-289) consider it. Since it seems 
not to have been reported, it will be described in detail as 
a contribution to our growing understanding of the nar- 
cotics of South America. 
In the very headwaters of the Igarapé Peritomé, a 
small creek on the right bank of the Rio Apaporis into 
which it empties slightly downstream from the great 
falls known as the Cachivera de Yayacopi or Raudal de 
La Playa, there is a small group of ‘Tanimuka Indians 
living entirely detached from the main body of the tribe 
on the Rio Popeyaca to the east (See map). This group, 
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