482 
Headache  Mixtures. 
(  Am.  Jour.  Pharm, 
t     October,  1909. 
desired  on  a  steam  or  hot-water  bath  to  dryness,  in  the  latter  case 
partially  covering  the  dish  toward  the  end  of  operation  with  a  watch- 
glass  in  order  to  avoid  possible  loss  from  "  popping."  Cool  in 
desiccator  and  weigh  as  caffein,  dry  alkaloid.3 
Acetanilid. 
First  Method. — The  acid  solution  remaining  in  the  separator  and 
containing  aniline  sulphate  is  run  into  a  100  c.c.  Erlenmeyer,  the 
filter  through  which  the  chloroform  passed  is  washed  once  with  a 
little  water,  allowing  the  latter  to  run  into  the  separator.  Rinse  the 
latter  thoroughly,  adding  the  aqueous  rinsings  to  the  acid  solution. 
Now,  run  in  slowly  and  with  constant  agitation  a  standard  solution 
of  potassium  bromide-bromate  4  to  a  faint  but  distinct  yellow  color- 
ation. The  number  of  cubic  centimetres  employed,  multiplied  by 
the  value  of  I  c.c.  in  terms  of  acetanilid,  will  give  the  amount  of 
acetanilid  present. 
Second  Method. — The  acid  solution  aforesaid  is  treated  with 
successive  small  portions  of  sodium  bicarbonate  until  an  excess  of 
this  reagent  is  observed  in  the  bottom  of  the  separator.  Add  50  c.c. 
of  chloroform  and  15  to  20  drops  of  acetic  anhydride,  shake  for 
some  time  vigorously,  allow  the  chloroform  to  clear,  then  pass 
through  the  same  filter  used  for  the  caffein  into  a  100  c.c.  Erlen- 
meyer, and  distil  off  most  of  the  chloroform.  Use  this  distillate 
for  a  second  shake  out,  clear,  filter,  and  distil  down  to  a  small 
volume,  transferring  the  residue  and  the  subsequent  chloroform 
3  Should  the  caffein  not  be  colorless  or  nearly  so,  the  residue  is  dissolved 
in  about  10  c.c.  of  water,  filtered,  if  necessary  (in  case  oily  matters  are 
present),  through  a  wet  filter,  the  filtrate  acidified  with  dilute  hydrochloric 
acid,  the  caffein  precipitated  with  15  to  20  c.c.  of  Wagner's  reagent,  allowed 
to  stand  a  half  hour,  filtered,  and  the  precipitate  washed  with  a  few  cubic 
centimetres  of  same  reagent,  the  filter,  together  with  precipitate,  transferred 
to  separator,  decolorized  by  means  of  sodium  sulphite,  and  the  caffein 
finally  extracted  with  chloroform. 
4  For  this  purpose  the  solution  is  prepared  by  adding  bromin  in  slight 
excess  to  a  concentrated  aqueous  solution  of  50  grammes  caustic  potash, 
the  liquid  diluted  till  the  separated  salts  redissolve,  boiled,  to  expel  any 
excess  of  bromin,  and  finally  made  up  to  1  litre.  This  solution  is  standar- 
dized with  weighed  amounts  of  acetanilid,  or  it  may  be  so  adjusted  by 
further  dilution  that  1  c.c.  is  exactly  equivalent  to  1  centigramme  of  acetan- 
ilid. For  purposes  of  titration  1  to  2  decigrammes  are  heated  a  half  hour 
on  the  steam  or  water  bath  with  10  c.c.  of  dilute  sulphuric  acid. 
