September? 19m  }      Scammony  and  Resin  Scammony.  429 
the  root  of  Ipomceq  orizabensis.  This  substance  is  not  yet  official 
in  any  of  the  pharmacopoeias. 
The  subject  is  further  complicated  by  the  difficulty  of  procuring 
authentic  samples.  The  dealers  frequently  confuse  names,  and, 
judging  by  our  analytical  results,  substitution  very  often  takes 
place.  As  an  example,  one  lot  of  root  shipped  as  genuine  Mexican 
scammony  was  labelled  "  Convolvulus  Scammonia,  Mexican,"  which 
is  of  course  contradictory. 
The  work  of  Guigues  dealt  principally  with  the  solubility  of  scam- 
mony resin  in  ether,  and  with  the  optical  rotation.  He  found  that 
some  scammony  resins  were  partly  insoluble  in  ether,  while  the  resin 
from  Ipomcea  orizabensis  is  completely  soluble  in  ether  and  can  be 
used  to  adulterate  true  scammony,  a  statement,  which,  as  will  be 
"shown  later,  is  incorrect.  He  also  called  attention  to  the  necessity 
of  using  ether  of  a  definite  degree  of  hydration  and  alcohol  percent- 
age when  determining  the  solubilities. 
As  regards  the  optical  rotation  for  resin  extracted  from  the  gum 
resin  (scammony),  Guigues  found  a  maximum  specific  rotation  of 
— 24.5 °.  For  resin  extracted  from  the  root,  the  rotation  varied 
from  — 18.50  to  —23.5°. 
The  work  of  Cowie  showed  that  the  saponification  value  is  a 
simple  and  accurate  means  of  distinguishing  true  scammony  resin 
from  Mexican  resin.    Cowie  also  studied  the  solubility  in  ether. 
Taylor  has  also  made  a  rather  extended  study  of  the  acid  and 
saponification  numbers,  ether  solubilities,  and  iodine  numbers  of 
various  scammony  resins.  According  to  his  statement,  however, 
all  these  resins  were  prepared  by  extracting  the  roots  with  alcohol, 
and  hence  none  of  them  can  be  regarded  as  U.S. P.  products. 
Cowie  does  not  give  any  details  as  to  the  history  of  most  of  his 
resins,  but  it  appears  that  most  of  them  were  commercial  samples, 
or  purified  resins  obtained  from  commercial  articles.  If  his  resins 
were  prepared  by  purifying  virgin  scammony,  they  would  come 
under  the  class  of  the  U.S. P.  resin  scammony,  but  would  not  be 
official  in  the  British  Pharmacopoeia,  and  vice  versa,  if  they  were 
made  by  extracting  the  drug,  they  would  be  official  in  the  British 
Pharmacopoeia  and  not  in  the  U.S. P.  This  instance  shows  the 
difficulty  of  arriving  at  definite  conclusions  in  these  matters. 
The  chief  results  of  Taylor's  and  Cowie's  work  have  been  to 
show  that  the  saponification  values  for  resins  iromC  outoIvuIus scam- 
monia range  around  the  number  238,  while  the  saponification  values 
