drogue simple a caféine’’ Bull. Sci. Pharm. 38 (1926) 587- 
539—Trav. Lab. Mat. Méd. 17, pt. 6° (1926)—Compt. 
Rend. 182 (1926) 1494—Chem. Zentralbl. 1 (1927) 138) 
reported on the chemical constitution of yoco stems re- 
ceived from Dr. Claes and from a French consular official 
in Quito, Ecuador. At the time of the publication of 
this report, the plant had not been identified even as to 
the family. For this reason, Rouhier and Perrot were 
forced to refer to the plant simply as “‘le yocco, nouvelle 
drogue simple 4 caféine.”’ As I have indicated above, it 
is probable that these plant materials, which shortly after 
the appearance of Rouhier and Perrot’s paper were mis- 
takenly identified as Paullinia scarlatina, are referable to 
Paullinia Yoco. 
According to Rouhier and Perrot, yoco “‘bark’’ (by 
which is meant probably all tissues outside of the xylem) 
contains 6.1% ash, 12.89% water, and 2.739% caffeine. 
Michiels and Denis (Journ. Pharm. Belg. 8 (1926) 795— 
Chem. Zentralbl. 1 (1927) 188) report that the inflores- 
cences of yoco also contain caffeine. ® 
Thus, yoco may be added to that list of plant species 
which are rich in caffeine. Among the more important 
‘affeine-yielding plants are: coffee (Coffea arabica L. and 
other species) of the Rubiaceae; tea (Camellia sinensis 
(L.) O. Ktze.) of the Theaceae; kola nut (Cola nitida 
(Vent.) A. Chev.) and cacao (Theobroma Cacao LL.) of 
the Sterculiaceae; maté (Ilex paraguariensis St. Hil.) 
of the Aquifoliaceae; and guarand (Paullinia Cupana 
HBK.) of the Sapindaceae. 
In all of these species, the highest caffeine concentra- 
tion is found in the leaves, fruits or seeds. Consequently, 
these are the economically important parts of the plant. 
3 . wigew 7 ‘ : r 
The chemical composition of yoco has been summarized in Wehmer : 
ee . 
Die Pflanzenstoffe,’’ ed. 2, 2 (1931) 730. 
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