684 
Study  of  Strophanthus  Kombe  Seeds.    { Am.  jour.  Pharm. 
*      J  1  1     October,  19 19. 
chloroform  used  and  assure  complete  removal  of  the  strophanthidin. 
The  same  B.P.  tincture  assayed  bv  Barclay's  method  and  using-  the 
perforator  gave  0.099  Per  cent,  of  strophanthin. 
In  assaying  the  seeds  by  Fromme's  and  Lampart  and  Mueller's 
methods,  I  was  unable  to  remove  completely  the  bitter  principle  by 
the  methods  they  used,  which  consist  in  exhausting  the  seeds  with 
absolute  alcohol.  It  is  probable  that  the  samples  of  seeds  they  inves- 
tigated were  not  as  rich  in  the  glucoside  as  the  sample  I  investigated. 
In  the  assay  of  the  seeds,  I  found  it  better  that  the  extraction  should 
be  done,  not  by  absolute  alcohol,  but  by  65  per  cent,  alcohol  in  a  long 
narrow  percolator  till  the  seeds  were  free  from  bitterness. 
Working  under  the  same  conditions,  I  tried  a  series  of  experi- 
ments for  exhausting  the  de-fatted  seeds  and  examining  both  the 
tincture  and  the  marc  obtained,  and  arrived  at  the  following-  con- 
elusions  : 
1.  Absolute  alcohol  is  not  a  good  solvent  for  the  active  principle 
present  in  the  seeds. 
2.  The  lower  the  percentage  of  alcohol,  the  more  rapid  is  the  re- 
moval of  the  active  principle  from  the  seeds. 
3.  A  lower  percentage  of  alcohol  than  65  per  cent.,  though  it  ex- 
tracts the  bitter  principle  more  rapidly,  yet  it  produces  an  unsightly 
tincture,  which  is  not  clear,  and  is  very  hard  to  filter. 
4.  Water  alone  is  unsuitable,  since  the  aqueous  tincture  decom- 
poses very  quickly;  a  precipitate  was  formed,  and  a  bad  odor  devel- 
oped within  two  days. 
5.  The  best  method  to  prepare  a  tincture,  on  the  large  scale,  is  to 
moisten  the  de-fatted  seeds  with  alcohol  65  per  cent.  Then  employ 
slow  extraction  (by  65  per  cent,  alcohol)  in  a  long  narrow  percolator 
till  the  seeds  are  free  from  bitterness.  A  sample  of  the  resulting 
tincture  should  be  assayed  both  chemically  and  physiologically,  and 
then  the  tincture  diluted  with  65  per  cent,  alcohol  to  an  official 
strength. 
This  method  of  procedure  is  suggested  since  different  samples 
of  seeds — and  hence  the  tinctures  prepared  from  them — vary  to  a 
considerable  extent  in  the  strophanthin  content. 
These  investigations  were  carried  out  in  the  pharmacological 
laboratories  of  the  Manchester  University,  and  I  take  this  oppor- 
tunity to  express  my  best  thanks  to  Professor  R.  B.  Wild,  M.D., 
M.Sc,  F.R.C.P.,  and  Mr.  J.  Grier,  M.Sc,  Ph.C,  for  their  valuable 
suggestions  and  criticism. 
