Am6ctobUerr,  \9um' }  The  Detection  of  Emo  din-Bearing  Drugs.  447 
residue  twice  moistened  with  alcohol  and  evaporated  in  order  to  re- 
move the  last  trace  of  acetone.  The  residue  was  taken  up  in  diluted 
sodium  hydroxide  solution,  the  solution  filtered,  and  a  slight  excess 
of  iodine  test  solution  added,  followed,  after  a  few  minutes,  by  a 
slight  excess  of  hydrochloric  acid.  The  container  was  cooled  for  an 
hour  in  a  water-bath  having  a  temperature  below  150  C.  and  the  con- 
tents filtered.  By  this  treatment  the  phenolphthalein  was  precipitated 
as  tetraiodophenolphthalein,  a  substance  which  is  very  insoluble  in 
water.  The  precipitate  on  the  filter  was  washed  with  water  several 
times,  a  yellow  solution  being  produced.  The  filtrate  and  washings 
were  united,  the  solution  treated  with  a  slight  excess  of  sodium  sul- 
phite to  remove  free  iodine,  and  the  solution  shaken  with  chloroform. 
The  chloroform  was  evaporated  and  the  residue  treated  with  dilute 
solution  of  sodium  hydroxide.  By  this  treatment  the  anthracene  pur- 
gatives give  red  colors  which  vary  in  shade,  depending  somewhat  upon 
the  source  of  the  emodin.  Preparations  containing  phenolphthalein 
alone  give  no  red  color,  or  at  most  a  faint  purplish-red,  which  soon 
fades  if  a  considerable  excess  of  the  alkali  be  added. 
Briefly  stated,  the  method  consists  in  treating  an  acetone  or  ether 
extract  of  the  substance  with  sodium  hydroxide  solution,  adding 
iodine  solution,  followed  by  hydrochloric  acid,  removing  the  tetraiodo- 
phenolphthalein by  filtration  after  standing,  shaking  out  the  filtrate 
with  chloroform  after  adding  a  sulphite  to  remove  excess  of  iodine, 
evaporating  the  chloroform,  and  treating  the  residue  with  sodium 
hydroxide  solution. 
As  controls  the  test  was  carried  out  with  the  fluidextracts  of 
cascara  and  rhubarb,  a  mixture  of  the  fluidextracts  of  senna  and 
licorice,  a  trade  preparation  stated  to  contain  senna,  a  mixture  con- 
taining aloes  and  phenolphthalein,  and  a  trade  preparation  claimed  to 
be  a  form  of  bitterless  cascara.  The  residue  from  the  fluidextract 
of  cascara  gave  a  dark  red  color  with  a  faint  brownish  tinge,  that 
from  rhubarb  a  deep  red  with  a  suggestion  of  purplish,  that  from 
the  senna-licorice  mixture  a  somewhat  lighter  red  with  a  faint  sug- 
gestion of  yellowish  (the  licorice  did  not  interfere),  that  from  senna 
alone  a  color  similar  to  that  from  the  mixed  senna  and  licorice,  that 
from  the  aloes  and  phenolphthalein  a  faint  reddish-yellow,  and  that 
from  the  bitterless  cascara  preparation  a  color  similar  to  that-  given 
by  the  fluidextract  of  cascara.  The  test  with  aloes  was  carried  out 
several  times,  but  with  results  that  were  not  entirely  satisfactory.  The 
colors  given  for  the  several  drug  residues  do  not  differ  from  each 
