21 8  Contributions  from  H.  M.  Gordin.  {Am-^/;^xm- 
Test  a  few  drops  of  the  aqueous  liquid,  after  acidulating,  with 
Wagner's  reagent.  If  no  reaction,  reject  it.  If  a  reaction  is  ob- 
tained, shake  the  liquid  again  with  20  c.c.  petroleum  ether  in  the 
second  separator,  reject  aqueous  liquid  and  transfer  the  petroleum 
ether  from  the  second  to  the  first  separator.  Now  add  about  05 
gramme  MgO  to  the  petroleum  ether  and  shake  well  about  fifteen 
minutes.  Filter  into  a  300  c.c.  flask,  washing  separator  and  filter 
repeatedly  with  petroleum  ether  and  keeping  funnel  covered  with 
a  watch-glass.  Add  50  c.c.  of  a  perfectly  clear  saturated  solution 
of  HC1  gas  in  absolute  ether,1  mix  well  and  distil  off  the  solvent 
from  a  warm  water-bath  completely,  removing  last  traces  by 
means  of  a  current  of  dry  air.    Now  add  to  the  flask  25  or  30  c.c. 
5.  AgN03  and  then  5  c.c.  10  per  cent.  HN03.    Put  on  water-bath,. 
and  when  the  supernatant  liquid  becomes  clear,  cool  the  flask, 
transfer  its  contents  into  a  100  c.c.  measuring  flask,  and  make  up 
the  whole  to  100  c.c.  Filter,  add  to  50  c.c.  of  the  filtrate  5  c.c.  test 
solution  of  ferric  alum  and  titrate  the  excess  of  silver  nitrate  with 
N' 
—  potassium  sulphocyanate  in  the  usual  way. 
40 
N 
The  number  of  cubic  centimetres  of        AgNOs  consumed  by  the 
40 
5  grammes  drug  multiplied  by  0-0635  gives  the  per  cent,  of  coniine 
in  the  drug. 
III.  ASSAY  OF  FLUID  EXTRACT  CINCHONA. 
In  a  previous  paper2  I  have  given  a  general  method  for  the 
assay  of  fluid  extracts.  As  given  there,  the  assay  of  fluid  cinchona 
gives  only  the  total  alkaloids,  but  as  it  seems  desirable  to  have  a 
method  that  would  show  both  the  total  and  the  ether  soluble  alka- 
1  If  water  be  present  in  the  ether,  the  ethereal  solution  of  HC1  will  be  turbid, 
and  when  the  ether  is  distilled  off  from  the  coniine  hydrochloride,  the  acid 
becomes  concentrated  in  the  last  aqueous  portions  and  colors  the  alkaloid 
greenish-red.  If  ether  containing  some  water  be  saturated  with  gaseous  HCL. 
and  the  solution  set  aside  for  a  few  hours,  all  the  water  will  settle  down,  taking 
along  most  of  the  HC1 ;  if  the  ether  be  now  poured  off  from  the  aqueous  layer 
and  again  saturated  with  HC1,  it  will  be  perfectly  clear  and  free  from  water. 
The  HC1  is  best  generated  by  dropping  commercial  hydrochloric  acid  from  a 
dropping  funnel  into  concentrated  acid  and  washing  the  gas  by  passing  it 
through  a  small  quantity  of  sulphuric  acid. 
2  Arch.  d.  Pharm.,  1900,  340  ;  Proceed.  A. Ph.  A.,  1900,  125. 
