ployed in the elaboration of the paste anda comparison of these 
methods with those followed by the Witoto Indians of the same 
original geographic area. 
The Karaparana Witotos select their trees by slashing a small 
strip of bark and tasting, sniffing and feeling the cambial layer, 
discarding trees which did not meet the right criteria: an ample 
cambial layer, bitter to taste and with a musty odour. That this 
custom is part of an old tradition was confirmed by an elderly 
Bora from the village of Tierra Firme on the Rio Ampiyacu who 
selected several Virolas and classified them according to their 
potency (which later chemical analysis proved to be correct): 
he had, in effect, chosen the species with the highest concen- 
tration of tryptamines as ascertained by his tasting and smelling 
the cut bark. 
It is obvious from our field observations in 1970 (Schultes & 
Swain, 1976) and 1977 that it is not the trees producing the most 
red resin that give the best preparation for inebriating effects or 
even contain the highest amount of tryptamines. Indeed, the 
Virola tree which produced the most copious amount of resin 
proved to contain no tryptamines either in the phloem or in the 
resin itself, although small amounts were found in the bark. 
Among the Boras, the first step consists in stripping bark 
from the trunk of the tree and carrying it back to the house for 
immediate processing. If the tree is standing in water (during 
the season of high water), the bark is stripped directly from the 
standing tree from a dugout canoe; if the tree grows on high 
land, the tree is usually felled for stripping. Strips of bark 
approximately two and a half feet long are cut from the tree 
with a machete, usually — and undoubtedly only for conveni- 
ence — from the lower four to eight feet of the trunk. If an 
unusually large amount of paste is to be prepared, bark is taken 
from other parts of the main trunk. 
This primary operation stands in sharp contrast to the Witoto 
method employed on the Karaparana where, in the forest, the 
shiny cambial layer left of the inner surface of the strips of bark 
and that are still adhering to the decorticated trunk is rasped off 
with the back of a machete, and the raspings are gathered 
carefully in a gourd for processing in the house (Schultes & 
Swain, 1976). 
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