ON  THE  DRIED  COFFEE-LEAF  OF  SUMATRA. 
249 
ON  THE  DRIED  COFFEE-LEAF  OF  SUMATRA. 
Which  is  employed  in  that  and  some  of  the  adjacent  Islands  as  a  substitute 
for  Tea  or  for  the'  Coffee-bean.. 
By  John  Stenhouse,  LL.  D.,  F.  R.  S. 
I  recently  received  from  my  friend  Daniel  Hanbury,  Esq.,  a 
quantity  of  dried  coffee-leaves,  which  had  been  prepared  in  Suma- 
tra, under  the  direction  of  N.  M.  Ward,  Esq.,  of  Padang.*  The 
sample  had  a  deep  brown  color,  and  consisted  of  the  leaves  of 
the  coffee-tree  mixed  with  fragments  of  the  stalks.  The  leaves 
had  been  very  strongly  roasted  in  rather  a  rough  manner,  and 
had  consequently  acquired  a  slightly  empyreumatic  odor.  In 
this  respect  they  pretty  closely  resemble  Paraguay  tea,  the  leaves 
and  twigs  of  the  Ilex  paraguayensis,  which  is  subjected  to  a 
somewhat  similar  process.  The  coffee-leaves,  when  digested  with 
boiling  water,  yielded  a  deep  brown  infusion,  which  in  taste  and 
odor  closely  resembled  an  infusion  of  a  mixture  of  coffee  and  tea. 
On  the  addition  of  milk  and  sugar,  it  formed  a  very  tolerable 
beverage ;  and  as  the  roasted  coffee-leaf  can  be  imported  into 
Europe  for  rather  less  than  twopence  per  pound,  the  poorer 
classes  are  likely  to  find  it  a  very  useful  substitute  for  tea  and 
coffee.  Should  a  more  moderate  temperature  be  employed  in 
drying  the  coffee-leaf,  I  think  its  flavor  would  be  greatly  im- 
proved. 
The  coffee-leaf,  as  might  almost  have  been  expected,  contains 
the  two  characteristic  constituents  of  the  coffee-bean,  viz.,  theine 
or  caffeine,  and  caffeic  acid.  In  this  respect  the  coffee-leaf  differs 
essentially  from  chicory  or  any  of  its  adulterations,  such  as 
roasted  turnips,  mangelwurzel,  carrots,  &c,  the  usual  substitutes 
for  coffee,  which  do  not  contain  a  trace  of  either  of  these  prin- 
ciples. 
The  theine  or  caffeine  was  extracted  from  the  coffee-leaves  in 
the  usual  way,  by  precipitating  the  coloring  matter  and  other 
impurities,  first  by  acetate  and  then  by  subacetate  of  lead.  The 
acetate  of  lead  threw  down  a  dark  brown  precipitate  containing 
all  the  caffeic  acid,  and  the  subacetate  produced  a  scanty  bright 
yellow  precipitate.  The  excess  of  lead  was  then  removed  from 
the  clear  solution  by  sulphuretted  hydrogen,  and  the  sulphide  of 
*  See  Vol.  XXV,  page  221  of  this  Journal. 
