this addition either heightens or lessens the normal nar- 
cotic effects of coca prepared in the manner customary 
throughout the northwest Amazon. It would seem to be 
obvious that the only effect sought is a change in taste. 
Thoroughly accustomed though I was to the use of 
coca at this time, I found that the resin-treated product 
usually caused irritation of the mouth and throat the 
first day of its use. This irritation, due undoubtedly 
wholly to the balsamic smoke absorbed by the ash- 
particles, disappeared upon continued use of the coca. 
Enquiry indicated that the resin of Protium heptaphyl- 
lum is the only one of the many balsamic exudations of 
the forests considered to be suitable for flavoring coca. 
According to Indian custom, resin for this purpose is 
gathered exclusively from old trees of Protium hepta- 
phyllum, but no ‘‘explanation’’ for avoidance of younger 
trees was offered. Incisions are made in the bark of the 
trees, and the resin is allowed to dry on the trunk before 
being gathered and wrapped up in leaves into little pack- 
ets which are hung under the rafters of the house to 
‘‘age’’ for four or five months before using. 
The genus Protiuwm, belonging to the Myrrh Family 
or Burseraceae, has given several resins to commerce and 
medicine, and the resins of allied genera have likewise 
enjoyed economic importance. Several species of Protium 
from northern South America have been of value as 
medicinal plants, but they are no longer so employed in 
the United States. 
The resin from Protium heptaphyllum, a species wide- 
spread in South America, is usually referred to in Co- 
lombia as brea or pergamin, but it is known commercially 
as tacamahaca gum. These vernacular names, however, 
may also be applied to the resins of other burseraceous 
plants. This species yields a hard, translucent, white resin 
which easily fractures and which is distinctly pungent 
[ 245 ] 
