Am.  Jour.  Phaim. 
March.  1901. 
The  Assay  of  Coca. 
129 
The  acid  solution  is  now  drawn  off  carefully  into  a  third  separator  ; 
the  ether  remaining  in  the  first  separator  is  shaken  successively 
with  two  portions  of  water  of  5  c.c.  each ;  after  separation  has  taken 
place,  these  in  their  turn  are  added  to  the  second  ether  washing, 
and  after  shaking  and  allowing  to  separate,  are  drawn  off  into  the 
third  separator  containing  the  major  portion  of  the  acid  solution. 
To  this  is  then  added  a  sufficient  quantity  of  ammonia  water  10 
per  cent.,  previously  diluted  with  four  times  its  volume  of  water,  to 
render  the  liquid  slightly  alkaline. 
If  the  ammonia  water  used  is  of  proper  strength,  then  6  64  c.c. 
of  the  dilution  will  be  sufficient.  However,  in  practice  it  usually 
requires  from  8  to  9  c.c. 
This  method  of  procedure  prevents  an  unnecessary  excess  of 
alkali  which,  as  has  been  pointed  out,  exerts  a  saponifying  effect 
upon  the  alkaloids,  proportional  to  the  degree  of  its  concen- 
tration. 
(To  satisfy  one's  self  of  this  fact,  it  is  only  necessary  to  add,  say 
5  c.c.  of  10  per  cent,  ammonia  water  for  the  precipitation  of  the 
alkaloids,  and  to  remove  them  by  extracting  with  successive  por- 
tions of  ether,  until  this  latter  upon  evaporation  leaves  no  weigh- 
able  residue. 
If  now,  to  a  portion  of  the  alkaline  liquid  remaining,  a  few  drops 
of  Mayer's  reagent  be  added,  an  unmistakable  evidence  of  the  pres- 
ence of  benzoyl-ecgonine  will  be  recognized.) 
Extract  now  the  alkaloids  with  three  successive  portions  of  ether, 
using  respectively  40,  30,  30  c.c,  taking  care  in  each  instance  to 
allow  the  ether  to  separate  completely,  drawing  off  the  aqueous 
liquid  carefully  into  another  separator,  and  pouring  the  ethereal 
solution  of  the  alkaloids  out  through  the  upper  opening  of  the 
separator  into  a  tared  beaker  of  160  c.c.  capacity. 
Rinse  the  separator  with  10  c.c.  of  ether,  pouring  it  out  at  the 
top,  into  the  separator  containing  the  aqueous  portion. 
Now  hold  the  separator  from  which  the  ethereal  solution  has  just 
been  removed,  in  the  left  hand,  with  the  mouth  of  same  inclined 
downward  at  an  angle  of  about  45 0  with  and  over  that  of  the  sepa- 
rator containing  the  aqueous  portion,  and  while  rotating  same, 
rinse  the  rim  with  5  c.c.  of  ether  delivered  from  a  dropping  tube  in 
such  a  way  that  in  falling  it  will  drop  into  the  separator  beneath; 
in  a  similar  manner  rinse  the  cork  stopper,  and  finally  add  to  the 
