68 
AMOUNT   OF  THEINE  IN  GUARANA. 
in  these  two  forms  as  due  only  to  a  different  cohesion  and  me- 
chanical resistance.  The  multiplicity  of  surfaceSj  and  the  facili- 
ty of  movement  in  the  powder,  hasten  its  alteration  in  water. — 
Ohem.  Graz.,  Sept.  15,  1856,  from  Comptes  Bendus,  July  21, 
1856,  p.  117. 
DETERMINATION  OF  THE  AMOUNT  OF  THEINE  IN  GUARANA. 
By  John  Stenhouse,  LL.  D.,  F.  R.  S. 
Guarana,  as  is  well  known,  is  a  species  of  chocolate,  manufac- 
tured from  the  fruit  of  the  Paullinia  Sorbilis,  by  the  aboriginal 
tribes  of  Para,  and  other  districts  in  Brazil,  and  extensively  em- 
ployed by  them  both  as  a  refreshing  beverage,  and  as  a  remedy 
against  dysentery  and  similar  diseases. 
The  presence  of  theine  in  guarana  was  first  discovered  many 
years  ago  by  Dr.  Theodore  Martius,  of  Erlangen,  and  his  obser- 
vations were  subsequently  corroborated  by  Messrs.  Berthemot, 
Bechastelus,  and  0.  Jobst. 
As  none  of  these  gentlemen,  however,  made  any  determination 
of  the  amount  of  theine  in  guarana,  I  thought  it  might  be  of  some 
interest  to  supply  the  omission,  especially  as  I  had  previously 
determined  the  quantity  of  theine  present  in  all  the  other  sub- 
stances known  to  contain  that  alkaloid.  Through  the  kindness 
of  my  friend  John  Miers,  Esq.,  F.  B.  $.,  the  well-known  Bra- 
zilian traveller,  I  have  recently  been  enabled  to  subject  guarana 
to  a  new  examination. 
The  specimen  of  Guarana,  given  me  by  Mr.  Miers,  was  about 
seven  and  a  half  inches  long,  one  and  a  quarter  inches  thick,  and 
weighed  nearly  three-quarters  of  a  pound.  It  had  a  rough  cor- 
rugated surface,  dark  brown  color,  no  odor,  and  a  somewhat 
amygdaloidal  fracture. 
Twenty-five  grammes  of  the  specimen  were  very  finely  powder- 
ed, and  boiled  with  one  quart  of  distilled  water  for  some  time. 
When  cold,  a  slight  excess  of  basic  acetate  of  lead  was  added, 
when  a  bulky  brownish-red  precipitate  fell.  This  was  repeatedly 
digested  with  hot  water,  and  the  clear  liquid  which  passed  through 
the  filter  was  treated  with  a  slight  excess  of  sulphuretted  hydro- 
gen, till  all  the  lead  present  in  it  was  precipitated.  The  clear  solu- 
tion was  then  evaporated  to  dryness  on  the  water-bath,  and  the  resi- 
