Am.  Jour.  Pharni.  "I 
tfarch,  1909.  J 
Determination  of  Alcohol. 
137 
alcoholic  determinations  of  which  are  vitiated  by  mechanically 
carried-over  oils,  etc.  (examples,  flnidextracts  of  cubeb,  buchu, 
sandalwood,  etc.  ),  that  it  was  deemed  worth  while  to  undertake  to 
modify  this  "  wine  "  method  so  as  to  make  it  applicable  in  these 
cases.  Although  by  no  means  has  a  sufficient  amount  of  work  yet 
been  done  upon  it  to  justify  our  concluding  either  to  condemn  or  to 
laud  the  modified  method,  the  results  so  far  obtained  are,  to  say  the 
least,  encouraging. 
Theoretically,  in  the  absence  of  substances  other  than  alcohol, 
volatile  at  water-bath  temperature,  the  method  would  work  as  well 
with  a  fluidextract  or  a  tincture  as  with  a  wine,  provided  only  that 
on  dilution  to  original  volume  with  water  a  clear  solution  results, 
the  production  of  a  clear  solution,  free  from  residue  or  precipitate, 
being  essential  to  correctness  of  results.  To  insure  such  a  final 
clear  solution,  therefore,  I  proposed  to  make  the  dilution  with  water, 
as  in  the  regular  method,  wherever  water  would  answer,  but  when 
it  would  not,  to  use  instead  a  definite  volume  of  an  alcohol  of  suit- 
able definite  specific  gravity. 
In  order  to  try  out  the  proposed  method  approximately  I  selected 
as  my  experimental  material  a  25  per  cent,  aqueous  solution  of 
extract  of  taraxacum,  for  the  reason  that  such  a  solution  can  be, 
theoretically  at  least,  diluted  with  either  water  or  alcohol  without 
precipitation.  From  this  was  prepared,  by  mixture  with  definite 
volumes  of  U.  S.  P.  alcohol  (specific  gravity  0.8106  at  22 0  C.) 
solutions  A,  B  and  C,  containing  respectively  25,  50  and  75  per  cent, 
by  volume  of  the  above  alcohol — these  solutions  being  made  up  to 
the  required  volume  in  each  case  with  the  aqueous  extract  taraxa- 
cum solution,  at  the  same  temperature  (22°  C).  These  solutions 
A,  B  and  C  respectively  contained,  therefore,  theoretically  (approxi- 
mately) 23.75,  47.5  and  71.25  per  cent,  of  absolute  alcohol  by 
volume. 
The  following  directions  were  then  carried  out  in  the  laboratory : 
1.  Determine  alcohol  (duplicates)  by  regular  method  by  distillation. 
2.  Determine  alcohol  by  regular  "wine"  method  as  follows  (duplicates)  : 
Take  specific  gravity  (Westphal)  at  definite  temperature  (Gr.  No.  1). 
Measure  50  c.c.  in  a  pipette  (at  same  temperature)  which  will  discharge 
the  exact  amount  of  liquid  necessary  to  fill  a  50  c.c.  cylinder  to  50  c.c.  mark, 
and  transfer  to  a  shallow  capsule.  Evaporate  on  water-bath  until  all  alcohol 
has  been  dissipated.  Transfer  residue  to  the  50  c.c.  cylinder  and  wash  capsule 
and  stirring  rod  with  distilled  water,  into  cylinder.  Finally  dilute  to  the 
mark  with  water  with  the  solution-  at  exactly  same  temperature,  and  take 
specific  gravity  (Westphal)   (Gr.  Xo.  2). 
