250 
ON  THE  DRIED  COEFEE-LEAF  OF  SUMATRA. 
lead  having  been  collected  by  filtration,  the  theine  crystallized 
when  the  liquid,  after  being  sufficiently  concentrated,  had  been 
set  aside  in  a  cool  place  for  some  days. 
The  crystals  of  theine  as  first  obtained  were  of  a  brownish 
color,  but  after  being  strongly  pressed  between  folds  of  blotting- 
paper  and  repeatedly  crystallized,  they  were  rendered  nearly 
colorless. 
L  1000  grains  of  dried  coffee-leaves,  when  treated  in  the  way 
just  described,  yielded  12.5  grains  theine  =  1.25  per  cent. 
II.  1000  grains  of  coffee-leaves  in  a  subsequent  trial,  gave 
11.54  grains  =  1.15  per  cent. 
The  amount  of  nitrogen  in  the  dried  coffee-leaves  was  also 
determined  by  Will's  method. 
1.344  grm.  substance  gave  0.2005  platinum  =  2.118  per  cent, 
nitrogen. 
0.7775  grm.  gave  0.1185  platinum  =  2.165  per  cent. 
Now  it  has  been  ascertained  as  the  result  of  numerous  experi- 
ments,* that  "coffee  contains  from  0.80  to  1  per  cent,  of  theine, 
and  that  tea  contains  1  per  cent,  of  the  same  principle."  "  And 
the  nitrogen  in  coffee-beans  (see  page  27  of  the  same  Report)  lies 
between  2|  and  3  per  cent." 
By  a  recent  determination  I  found  that  1000  grains  of  a  good 
black  tea  gave  21.3  grains  of  theine  =  2.13  per  cent. 
1000  grains  of  a  black  tea  grown  in  the  East  India  Company's 
tea  plantations  at  Kemaon,  on  the  Himalayas,  gave  19-7  grains 
—  1.97  per  cent. 
0.4705  grm.  of  the  same  Kemaon  tea  gave  0.1175  platinum 
=  3.5  per  cent,  nitrogen. 
Many  years  ago  I  detected  the  existence  of  theine  in  what  is 
called  Paraguay  tea,  the  dried  leaves  and  twigs  of  the  Ilex  para- 
guayensis,  but  I  neglected  to  determine  its  amount.  I  have  re- 
cently found  that  1000  grains  of  Paraguay  tea  yielded  12.3  grains 
of  theine  =  1.23  per  cent. 
III.  1000  grains  ditto  gave  11  grains  =  1.1  per  cent. 
1.748  grm.  gave  0.1865  platinum  —  1.51  nitrogen. 
*  See  the  32nd  page  of  the  "  Chemical  Report  on  the  Mode  of  Detecting 
Vegetable  Substances  mixed  with  Coffee,  for  the  purposes  of  adulteration/' 
drawn  up  hy  Professor  Graham,  Dugald  Campbell,  Esq.,  and  myself,  for 
the  British  Government,  and  communicated  to  it  in  December,  1852. 
