32 
Tincture  of  Nux  Vomica. 
Am.  Jour.  Pharm. 
Jau.,1884. 
which  we  have  already  proved  in  a  previous  communication  to  this 
Society  (see  "Amer.  Pharm.  Jour./'  pp.  268  and  467).  There  are, 
however,  other  possible  causes  Avhich  might  contribute  to  the  incon- 
stant result.  Foremost  among  these  is  the  possibility  of  alcohol  contain- 
ing more  water  than  rectified  spirit  having  been  employed  in  the  manu- 
facture of  the  tincture ;  this  conjecture  might  appear  to  be  supported 
by  a  relation  which  is  noticed  in  the  table  of  analyses  published  in  our 
previous  paper  upon  this  subject.  For  it  is  here  observed  that  in  cer- 
tain cases  high  specific  gravity  is  associated  with  a  large  percentage  of 
alkaloid.  The  important  assumption  underlying  this  conjecture  is  that 
a  dilute  alcohol  extracts  more  alkaloid  than  a  stronger  alcohol ;  but,  as 
far  as  we  can  discover,  this  has  never  been  experimentally  substantiated. 
Nevertheless,  various  suggestions  based  upon  this  assumption  have  been 
made  for  the  employment  of  a  weaker  alcohol  than  rectified  spirit  for 
the  preparation  of  the  tincture,  and  some  of  these  suggestions  have 
been  adopted  in  foreign  pharmacopoeias. 
In  order  to  determine  by  direct  experiment  the  extractive  power  of 
alcohol  of  different  strengths  the  following  experiments  were  made. 
Five  gram  quantities  of  nux  vomica  in  impalpable  powder  were  mace- 
rated for  three  days  with  50  cubic  centimetres  of  alcohol  containing 
different  proportions  of  water,  the  mixtures  being  frequently  agitated. 
Maceration  was  adopted,  because  percolation  with  alcohol  containing 
more  water  than  proof  spirit  is  rendered  practically  impossible  owing 
to  swelling  of  the  seeds  and  consequent  clogging  of  the  percolator, 
occasioned  by  the  action  of  the  water  upon  the  mucilaginous  con- 
stituents, and  it  was  deemed  important  that  the  experiments  should  be 
strictly  comparative.  And  further,  had  ordinary  percolation  been 
adopted  and  a  larger  amount  of  alkaloid  been  found  to  be  extracted 
by  the  weaker  spirit,  there  would  be  the  alternative  that  this  was  due, 
not  to  the  greater  solubility  of  the  alkaloidal  salts  in  the  weaker  spirit, 
but  to  the  longer  time  during  which  the  seeds  were  in  contact  with 
this  spirit,  for  with  nux  vomica  the  rate  of  percolation  is  inversely  as 
the  quantity  of  water  present.  After  maceration  forty  cubic  centi- 
metres of  the  tincture  were  filtered  off  and  the  amount  of  total  alka- 
loid determined  by  a  process  which  has  been  described  in  general  out- 
line in  our  former  paper  upon  tincture  of  nux  vomica. 
In  detail  the  process  is  as  follows :  The  quantity  of  tincture  to  be 
estimated,  usually  50  grams,  is  evaporated  almost  to  dryness  upon  the 
water-bath  in  a  beaker ;  to  this  residue  25  cc.  of  chloroform  are  added, 
