Am.  Jour.  Pharm. 
Sept.,  1889. 
Tincture  oj  Strophanthus. 
455 
The  seed  and  glass  are  ground  together,  the  powder  spread  out 
thinly  and  dried  at  110°  F.  Then  pack  it  tightly  in  a  percolator  and 
percolate  with  ether  until  free  from  oil.  The  ether  is  then  recovered 
by  distillation.  The  powder  is  again  spread  out,  dried  and  weighed, 
and  this  weight  plus  the  weight  of  the  oil  is  to  be  taken  as  the  weight 
of  the  seed  upon  which  to  adjust  the  yield  of  tincture.  Repack  the 
percolator  and  percolate  it  slowly  until  84  parts  of  tincture  are  ob- 
tained for  every  five  parts  of  dry  seed.    (Ephemeris,  July,  p.  1252.) 
There  are  several  new  features  introduced  in  this  formula  worthy 
of  comment.  Dr.  Squibb  makes  a  calculation  "to  convert  the 
British  relation  of  one  avoirdupois  ounce  to  twenty  British  fluid- 
ounces — or  of  weight  to  measure — to  the  more  accurate  and  convenient 
relation  of  the  U.  S.  P.,  of  weight  to  weight."  The  result  of  this 
calculation  the  Doctor  states  in  the  odd  proportion  of  5  parts  of  the 
seed  to  84  parts  of  the  tincture.  This  calculation  is  based  on  the 
assumption  that  because  an  alcohol  of  sp.  gr.  *8914  produces  a  tincture 
of  '8931  sp.  gr.  a  tincture  of  '840  sp.  gr.  would  be  produced  by  recti- 
fied spirits  B.  P.  #838  sp.  gr.  This  assumption  is  more  apt  to  be 
erroneous  than  correct.  The  truth  most  probably  is  that  different 
samples  of  seed  will  yield  various  percentages  of  extract  to  alcohol, 
and  certainly  the  same  seed  will  yield  a  larger  percentage  as  the  pro- 
portion of  water  is  increased.  In  confirmation,  I  would  call  attention 
to  the  results  of  H.  Helbing  (Phar.  Jour,  and  Trans.,  March  12, 
1887,  p.  747).  "A  tincture  prepared  with  rectified  spirits  has  the 
sp.  gr.  *840  and  a  fluidounce  yields  about  120  mgm.  of  residue  on 
evaporation.  Three  commercial  samples  had  nearly  the  same  density, 
but  yielded  respectively  88,  124  and  180  mgm.  of  residue.  Four 
other  tinctures  were  probably  made  with  a  weaker  alcohol,  were  of  a 
green  or  yellow  color,  varied  between  *870  and  *900  in  density  and 
yielded  from  170  to  242  mgm.  of  residue."  (See  Am.  Jouk.  Phar., 
1887,  p.  425.) 
It  seems  to  me  that  it  would  be  better  for  us  to  at  once  adopt  a 
strength  of  5  per  cent.,  1  part  of  the  dried  and  powdered  seed  to  20 
parts  by  weight  of  the  finished  tincture.  The  necessity  for  absolutely 
conforming  to  the  British  formula  in  this  country  does  not  seem  to 
be  so  imperative  when  we  compare  the  strengths  of  some  of  the 
poisonous  tinctures  of  the  U.  S.  and  Br.  Pharmacopoeias. 
Tr.  Aconiti,  U.  S.  P.,  is  40  per  cent.    Br.  Ph.  is  1  oz.  to  8  fl.  ozs. 
Tr.  Belladonna?,  U.  S.  P.,  is  15  per  cent,  Br.  PI  i.  is  1  oz.  to  20  fl.ozs. 
