128 
The  Assay  of  Coca. 
/Am.  Jour.  Pharui. 
\  Marcb,1901. 
gradually  add  75  c.c.  of  kerosene  oil,  stirring  well  after  each  addi- 
tion. 
After  the  whole  has  been  intimately  mixed,  cover  the  jar  and  al- 
low to  further  macerate  for  an  hour  or  more,  stirring  at  intervals  of 
ten  or  fifteen  minutes. 
Transfer  to  a  cylindrical  percolator  of  500  c.c.  capacity  (preferably 
of  the  Oldberg  type)  containing  a  plug  of  absorbent  cotton  firmly 
pressed  into  its  throat ;  pack  only  slightly. 
Remove  the  last  portions  of  the  leaf  from  the  jar  by  means  of  oil 
delivered  from  a  wash  bottle,  allowing  this  to  pass  through  before 
covering  with  a  fresh  supply. 
The  percolation  should  proceed  at  the  rate  of  six  or  eight  drops 
per  minute,  collecting  about  450  c.c.  of  percolate.  If  the  process  of 
percolation  is  carefully  executed,  a  smaller  quantity  of  percolate  suf- 
fices ;  sometimes  250  to  300  c.c.  are  sufficient  to  accomplish  a  prac- 
tical exhaustion  of  the  leaf. 
Transfer  the  percolate  to  a  separatory  funnel  of  700-750  c.c. 
capacity  of  the  Squibb  pattern,  and  after  rinsing  the  beaker  used  to 
receive  the  percolate,  with  small  portions  of  oil,  add  to  the  contents 
N 
of  the  separator  25  c.c.  of  —  hydrochloric  acid  and  shake  continu- 
10 
ously  lor  ten  minutes. 
Allow  the  separator  to  rest,  when  the  separation  will  be  almost 
completely  effected  in  twenty  minutes ;  draw  off  this  acid  liquid 
together  with  the  slight  amount  of  emulsion  remaining  at  the  line 
of  contact  of  the  two  liquids  into  another  separator  of  from  265- 
285  c.c.  capacity. 
Add  to  the  oil  remaining  in  the  separator  another  portion  of  25 
c.c.  —  hydrochloric  acid,  shaking  and  separating  as  just  described, 
10 
and  finally  the  extraction  is  completed  with  a  third  portion  of  25  c.c. 
N 
—  hydrochloric  acid. 
10 
To  the  united  acid  solutions  of  the  alkaloids  are  now  added  20  c.c. 
of  ether  and  the  whole  well  shaken  together.  After  carefully  releas- 
ing the  pressure,  the  liquids  are  allowed  to  separate,  the  acid  liquid 
is  then  drawn  off  into  a  second  separator  of  like  capacity  and  to  it 
is  added  a  fresh  portion  of  15  c.c.  of  ether,  the  two  well  shaken 
together  and  allowed  to  separate  completely,  thus  removing  the 
last  trace  of  oil  and  coloring  matter. 
