AlAp?iir'i92iarm' }       Preparation  of  Nux  Vomica.  269 
per.  Transfer  all  of  the  liquid  extract  into  the  flask  with  the  aid  of 
successive  portions  of  distilled  water,  employed  drop  by  drop ;  use 
the  rounded  end  of  a  fine  glass-rod  to  assist  in  the  transfer.  The 
final  volume  should  not  exceed  15  cc.  Coik  the  flask,  agitate  until 
a  homogeneous  mixture  is  obtained;  add  50  grammes  of  ether,  25 
grammes  of  chloroform  agitate  vigorously;  add  5  grammes  ammo- 
nia. Agitate  again  for  five  minutes.  Allow  to  settle  for  one  hour. 
Pour  the  supernatant  liquid  onto  a  dry  filter,  collect  50  grammes  in 
a  tared  Erlenmeyer  flask.  Distil  to  dryness  on  a  water-bath.  Add 
10  grammes  of  ether  to  the  residue  and  dry  on  the  boiling  water- 
bath  and  afterwards  in  a  hot  air-bath  at  ioo°  until  to  a  constant 
weight.  The  alkaloids  thus  obtained  are  pure,  brilliant  and  crystal- 
line. They  are  weighed  accurately.  They  represent  the  strychnine 
and  the  brucine  contained  in  2  grammes  of  liquid  extract.  This 
weight  multiplied  by  50  gives  the  percentage  of  alkaloids  present  in 
the  liquid  extract. 
N 
Volumetric  Control  of  the  Preceding  Result.   Twenty  -cc  of  — 
H2S04  are  added  to  the  alkaloidal  residue;  about  50  cc  of  hot  dis- 
tilled water  are  added.  The  Erlenmeyer  flask  is  placed  on  a 
water-bath  for  a  quarter  of  an  hour,  occasionally  agitating 
slightly.  It  is  filtered  on  a  wetted  filter;  the  filter  and  the 
Erlenmeyer  flask  are  washed  with  boiling  distilled  water ;  after  cool- 
ing, the  filtrate  is  made  up  to  200  cc.  100  cc  (correspond- 
ing to  1  gramme  of  the  liquid  extract)  are  taken.    Ten  drops  of 
N 
tincture  of  litmus  are  added,  and  —  KOH  is  added  until  a  change 
10  & 
of  color  *to  violet  from  deep  blue.    Let  n  cc  of  KOH  be  employed; 
(20-n)  x  0.0334  x  100  —  total  alkaloids,  expressed  in  strychnine, 
contained  in  100  grammes  of  liquid  extract. 
The  results  obtained  by  the  three  methods,  French,  Belgian, 
and  the  volumetric  that  I  have  explained,  coincide  almost  exactly; 
the  difference  is  only  of  the  order  of  the  hundredth  part;  the  result 
of  the  titration  by  the  French  method  is  always  higher  than  the  two 
others.   That  proves  that  volumetric  method,  is  as  it  should  be,  only 
a  means  of  control  of  the  gravimetric  method.    But  the  behavior  by 
change  of  color  with  litmus  has  this  important  advantage,  that  it  can 
be  placed  in  the  hands  of  anyone,  and  that  it  permits,  in  five  min- 
