OTHER    ALKALOIDS.  299

The  breaking  down  of  cocaine  was  subsequently  shown
due  to  hydration,  by  saponifying  it  with  baryta,  and  also  with
water  alone.  The  first  change  being  into  benzoyl-ecgonine,
followed  by  a  sublimation  of  benzoic  acid,  while  from  the
syrupy  residue  the  ecgonine  may  be  separated  by  repeated
washings  with  alcohol  and  precipitation  with  ether.  The
crystals  being  only  dried  with  great  difficulty.
Ecgonine,  C9H15NX)3,  crystallizes  over  sulphuric  acid  in
sheaves.  It  has  a  slight  bitter-sweet  taste,  is  readily  soluble
in  water,  less  so  in  absolute  alcohol,  and  insoluble  in  ether.
Heated  to  198°,  it  melts,  decomposes  and  becomes  brown.  It
forms  salts  with  the  acids,  most  of  which  crystallize  with  diffi-
culty. With  alkalies,  it  forms  crystallizable  combinations
soluble  in  water  and  alcohol.  In  aqueous  solutions  the  hydro-
chloride  yields  no  precipitate  with  alkalies.  Chloride  of
platinum  in  presence  of  much  alcohol  gives  an  orange  yellow
precipitate,  chloride  of  mercury  throwing  down  a  yellow  pre-
cipitate under  the  same  conditions.
The  unstable  nature  of  cocaine  in  the  presence  of  acids  has
suggested  their  avoidance  in  its  preparation,  plain  water
being  considered  preferable.  In  this  process  Coca  leaves  are
digested  several  times  at  140°  to  176°,  the  infusions  united,
precipitated  by  acetate  of  lead,  and  filtered.  The  lead  is  re-
moved by  the  addition  of  sulphate  of  soda,  and  the  liquor  con-
centrated in  a  water  bath.  Carbonate  of  soda  is  then  added,
and  the  whole  shaken  with  ether  to  dissolve  the  alkaloid,
when  the  ether  may  be  recovered  by  distillation.
