ure). The scraps of material thus obtained are squeezed 
to express the caffeine-bearing sap into cold water. If the 
yoco is rather old and dry, the rasped material is allowed 
to soak (plate xxix, lower figure) and the stimulating 
principles are quickly removed. After extraction, the re- 
mains of the rasped tissues are discarded. When prepared, 
yoco blanco is a cloudy milky-white liquid, but in the case 
of yoco colorado the liquid is light chocolate-brown in 
color. Both kinds are used without discrimination; ap- 
parently one is as strong a stimulant as the other. Yoco 
is never made with hot water. In this respect it differs 
markedly from Paullinia Cupana and other caffeine- 
yielding plants, for the extraction of caffeine from these 
plants is usually accomplished with warm or hot water. 
Each dosage of yoco consists of the expressed sap of 
approximately 90-100 grams of rasped material served in 
a ‘‘jicara,’’ a bowl made from the fruit of Crescentia 
Cuyete L. 
It is the general custom of the Indians of the Putu- 
mayo to eat nothing until noontime. Instead, yoco is 
taken each morning between five and six o'clock. One 
or two “‘jicaras,’’ each half full of the beverage, are suffi- 
cient to allay all sensations of hunger for at least three 
hours and to supply muscular stimulation. I have tried 
yoco on many occasions and find that the statements of 
the natives regarding the stimulating and hunger-allay- 
ing properties are not in the least exaggerated. The effects 
of the stimulant are rapid in action. A tingling of the 
fingers and a general feeling of well-being are noticeable 
ten minutes after drinking the contents of two “‘jica- 
ras.”’ IT have made long trips through the forests, and, 
taking nothing but yoco, have felt neither fatigue nor 
hunger. Klug (unpublished notes: ‘* Plants of Umbria, 
between the Rivers Alto Putumayo and Alto Caqueta, 
360 meters above sea level,’’ preserved in the United 
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