230 
Retina  Podophylli. 
{  Am.  Jour.  Phaem. 
t    May  1,  1874. 
tion,  though  more  slowly,  and  the  filtered  liquid  is  not  capable  of 
reducing  cupric  oxide  in  alkaline  solution. 
The  resin  fuses  at  220°  F.,  which  was  ascertained  by  placing  a 
portion  upon  the  surface  of  mercury,  with  a  thermometer  immersed 
in  the  liquid,  and  applying  a  carefully  regulated  heat ;  when  heated 
on  platinum  foil  it  melts  to  a  brownish  liquid,  and  upon  increasing 
the  heat,  takes  fire  and  burns  with  a  bright  sooty  flame  with  consider- 
able  empyreuma,  leaving  light  porous  charcoal.  Two  grams  of  the 
resin  were  boiled  with  a  fluidounce  of  water,  imparting  thereto  a  light 
yellow  color,  while  the  resin  ran  together,  forming  a  soft  brownish 
mass,  becoming  brittle  on  cooling.  The  liquid  was  filtered  while  hot, 
by  means  of  an  arrangement  for  hot  filtration,  it  was  transparent 
while  hot,  but  became  turbid  upon  cooling,  and  upon  evaporation  of 
the  liquid,  separated  resinous  flocks.  Upon  weighing  the  resin  after 
this  treatment  it  was  found  to  have  lost  0*03  grams.  The  ethereal 
resin  yielded  similar  results. 
The  resin  is  entirely  soluble  in  amylic  and  methylic  alcohol,  acetone, 
officinal  solution  of  potassa,  forming,  when  diluted,  a  bright  yellow 
solution  ;  it  is  also  soluble  in  carbolic  acid,  with  which  it  seems  to 
combine,  depositing,  upon  evaporation,  reddish  yellow  crystals,  but  is 
insoluble  in  turpentine. 
Supported  by  a  series  of  experiments  made  with  the  alcoholic  and 
ethereal  portions  of  this  resin,  I  can  confirm  the  statements  that  have 
been  previously  made,  that  while  the  portion  of  resin  insoluble  in 
ether  is  not  without  some  activity,  the  ethereal  resin  is  very  much 
more  active,  and  is  to  be  preferred  for  medicinal  use. 
By  the  following  tabular  statement,  the  relative  value  of  the  offici- 
nal resin,  as  compared  with  some  commercial  varieties,  will  be  seen 
based  upon  the  relative  activity  of  the  ethereal  and  alcoholic  resin ; 
all  were  found  to  be  free  from  admixture,  and  with  one  exception 
were  found  to  be  superior  to  many  specimens  of  western  manufacture  ; 
the  difference  in  color  is  probably  due  to  various  modifications  in  the 
process  of  preparation,  by  the  application  of  heat  in  the  separation  of 
the  resin,  which  no  longer  becomes  necessary  with  the  use  of  hydro- 
chloric acid,  or  by  the  addition  of  a  greater  or  less  amount  of  muriate 
of  berberina. 
No.  1.  U.  S.  Pharmacopoeia,  1870;  light  yellowish  brown.  No.  2. 
B.  A.  Hance,  Philadelphia :  bright  yellow.  No.  3.  Manufacturer 
unknown  :  dark  brown.    No.  4.  B.  Keith  k  Co.,  N.  Y.  :  yellowish. 
