ON  THE  CHEMICAL  CONSTITUENTS  OF  COCA  LEAVES.  499 
The  solution  from  which  the  alkaloid  had  been  removed  by 
ether,  was  digested  with  precipitated  carbonate  of  baryta,  which 
removed  all  the  sulphuric  acid,  and  acquired  a  pale  greyish 
white  color.  The  filtrate  was  neutralized  with  acetic  acid,  and 
after  the  expulsion  of  the  carbonic  acid,  rendered  very  slightly 
alkaline  by  a  few  drops  of  liquor  ammoniae.  An  aqueous 
solution  of  neutral  acetate  of  lead  was  now  carefully  dropped  in, 
as  long  as  a  dirty  greenish  brown  precipitate  was  produced, 
which  is  voluminous,  but  settles  in  a  few  minutes  and  may  be 
readily  filtered  and  washed.  On  the  further  addition  of  neutral 
acetate  of  lead  a  precipitate  is  separated  which  is  at  first  yellowish 
white,  but  settles  readily  to  a  greyish  yellow. 
The  liquid  filtered  from  this  last  precipitate,  is  not  disturbed 
on  the  further  addition  of  sugar  of  lead,  but  yields  with  basic 
acetate  of  lead  a  nearly  white  voluminous  precipitate  which  is 
insoluble  in  water,  but  readily  soluble  in  acids.  Corrosive  sub- 
limate and  deutonitrate  of  mercury  do  not  disturb  it;  protoni- 
trate  of  mercury  yields  a  whitish  precipitate,  insoluble  in  water, 
almost  entirely  soluble  in  nitric  acid ;  the  Avhite  precipitate  by 
nitrate  of  silver  is  scarcely  taken  up  by  nitric  acid,  but  readily 
by  ammonia.  The  liquid  contains  a  small  quantity  of  muriatic 
acid,  but  besides  it  an  organic  acid  which  imparts  to  it  a 
brownish  yellow  color.  This  color  becomes  deeper  on  exposure 
to  the  air,  and  after  24  hours  standing,  neutral  acetate  of  lead 
produces  a  precipitate  which  resembles  in  color  the  yellowish 
white  precipitate  spoken  of  before.  The  filtrate  was  now  of  a 
pale  yellow  color  and  was  not  further  disturbed  by  acetate  or 
subacetate  of  lead  after  exposure  to  the  air. 
The  first  of  the  above-mentioned  lead  compounds  dried  to  a 
dirty  yellowish  brown  powder ;  the  second  to  a  powder  of  a 
similar,  but  lighter  color. 
The  alkaloid  which  had  been  separated  by  ether  from  the 
alkaline  solution  left  behind  in  the  retort,  was  obtained  as  a 
transparent  mass  of  the  consistence  of  balsam  tolu,  a  somewhat 
lighter  color,  and  of  a  heavy  narcotic  odor.  All  attempts  to 
crystallize  it  failed,  but  it  had  still  an  alkaline  reaction  to 
test  paper,  was  insoluble  in  water,  but  soluble  in  acids,  which 
it  completely  neutralized.  The  solution  in  hydrochloric  acid 
yielded  with  alkalies  and  their  carbonates  a  white  precipitate 
