^ecemb^rf^iTl'  }  Advances  in  Pharmacy.  587 
dilute  alkali  causes  the  formation  of  a  red  color  in  the  water  layer 
if  emodin  or  other  anthraquinone  compounds  are  present.  The 
color  developed  by  phenolphthalein  disappears  in  the  course  of  an 
hour  or  so  in  the  presence  of  a  five  or  ten  per  cent,  potassium  or 
sodium  hydroxid  solution,  while  that  of  anthraquinone  compound 
is  permanent. 
Aloes  can  be  identified  by  the  fluorescence  occasioned  by  the 
addition  of  saturated  aqueous  solution  of  sodium  borate,  and  this 
no  matter  what  combination  of  emodin-containing  drugs  may  be 
present.  Rhubarb  occasions  a  deep  rose  color  with  sodium  borate, 
and  cascara  a  brown,  senna  sometimes  gives  a  light  brown,  but  gen- 
erally no  color  is  produced.  Rhubarb  can  be  distinguished  by  ob- 
taining a  positive  reaction  wTith  both  bleaching  powder  (red)  and 
iron  sulphate  (blue)  solutions;  so  far  as  is  at  present  known  no 
other  substances  will  give  both  reactions.  As  mentioned  above 
cascara  is  distinguished  by  the  brown  color  imparted  to  the  water 
solution  by  sodium  borate,  provided  the  two  tests  for  rhubarb  are 
negative.  It  is  likewise  possible  to  identify  cascara  in  any  com- 
bination of  emodin-containing  drugs  if  rhubarb  is  absent.  Senna 
is  the  hardest  to  detect  but  is  distinguished  by  its  failure  to  respond 
to  any  except  the  Borntrager  reaction.  This  reaction  is  the 
phenolphthalein  test  mentioned  above.  Experience  shows  that  it  is 
sometimes  difficult  to  get  senna  to  respond  even  to  this  test,  and 
this  may  be  due  to  the  fact  that  glucosides  of  the  anthraquinone 
compounds  are  present  in  larger  amounts  than  the  compounds 
themselves.  It  has  been  found  that  senna  cannot  be  distinguished 
in  combination  with  any  of  the  drugs.  The  fluorescence  sometimes 
brought  forth  by  cascara  solution  need  not  be  confounded  with 
aloes,  as  that  brought  forth  by  cascara  has  a  brown  color.  An 
aqueous 'solution  of  the  following  chemicals  on  ether  extractions  of 
these  emodin-containing  drugs  brought  color  reactions  as  follows : 
Ammonium  Thiocyanate — 
Senna :  Yellow  to  brownish  color  in  water  layer. 
Rhubarb :  Yellowish  color  in  water  layer. 
Cascara :  Brownish  to  rose-red  in  water  layer. 
Aloes  :  Red  in  ether  and  brown  in  water  layer. 
Ammonium  Molybdate — 
Aloes  and  Cascara :  No  color  change. 
Rhubarb :  Mahogany  brown  in  water  layer. 
Senna :  Very  light  brown  to  yellowish  in  water  layer. 
