12 
Substitute  for  Ethyl  Alcohol. 
(  Am.  Jour.  Pharm. 
\     January,  1869. 
detect,  and  the  want  of  sharpness  and  decision  in  this  end  reaction 
is  the  persisting*  difficulty  with  all  methods  of  titration  that  were 
tried,  but  in  comparing  indicators  brazilwood  was  found  to  be 
inferior  to  logwood.  A  decinormal  potassium  hydrate  is  preferable 
to  centinormal,  as  it  does  not  dilute  the  solution  of  alkaloids  so 
much,  while  in  accuracy  of  reading  it  is  far  within  the  limit  of  error 
of  the  indicator. 
Chiefly  in  consideration  of  these  conditions  the  following  method 
was  reached  and  used  : 
A  fair  sample  of  nux  vomica  is  drawn  and  an  average  dozen  or 
so  of  the  seed  is  so  milled  as  to  pass  through  a  No.  9  sieve.  Of 
this  10  grammes  is  weighed  off  and  exhausted  with  10  per  cent, 
acetic  acid.  This  exhaustion  is  easily  and  conveniently  done  in  a 
Soxhlet  apparatus,  but  so  large  an  amount  of  extractive  is  washed 
out  by  the  warm  acid,  that  the  extract  is  very  difficult  to  dry,  and 
afterwards  at  once  forms  an  emulsion  that  is  difficult  and  tedious  to 
manage.  Cold  percolation  to  complete  exhaustion  gives  a  much 
better  result,  and  is  not  difficult  to  effect,  provided  the  powder  be 
moistened  for  packing  with  not  more  than  10  c.c.  of  the  acetic  acid, 
and  be  not  packed  too  tightly. 
The  percolate  is  evaporated  to  dryness  on  a  water-bath,  in  a  large 
(12  centimetre)  flat-bottom  capsule,  so  that  the  extract  is  in  a  thin 
layer,  easy  to  dry  and  easy  to  dissolve.  The  weight  gives  the  yield 
of  extract. 
If  a  fluid  extract  or  tincture  is  to  be  assayed,  it  is  measured, 
weighed  and  dried  in  the  same  way. 
A  mixture  is  made  of  two  volumes  of  alcohol  (91  per  cent.),  one 
volume  of  water  of  ammonia  (10  per  cent.),  and  one  volume  of  water, 
and  of  this,  10  c.c.  is  poured  upon  the  dry  extract  in  the  capsule. 
Then  by  patiently  moving  a  stirrer  over  the  smooth  surface  of  the 
dry  extract  for  a  quarter  of  an  hour  or  more,  a  smooth  solution  of 
the  extract,  easy  to  wash,  is  obtained.  This  is  poured  into  a  sepa- 
rator of  1 50  c.c.  capacity,  and  the  capsule  and  stirrer  are  rinsed, 
clean  with  10  c.c.  more  of  the  alcohol  and  ammonia  solution. 
A  mixture  is  made  of  equal  volumes  of  chloroform  (99  per  cent.) 
and  ether  (96  per  cent.),  and  40  c.c.  of  this  is  added  to  the  liquid  in 
the  separator,  and  the  whole  is  shaken  vigorously  during  five  min- 
utes, and  then  allowed  to  separate.  In  twenty  to  thirty  minutes 
the  separation  will  be  complete  to  a  sharp  line,  when  the  depth  of 
