.300  Note  on  Recovering  Alcohol. 
NOTE  ON  RECOVERING  ALCOHOL. 
By  J.  U.  Lloyd. 
If  the  directions  for  preparing  official  fluid  extracts  are  carefully 
followed,  trouble  is  in  some  instances  experienced  in  the  very  important 
after-operation  of  recovering  the  alcohol  which  remains  within  the 
residue.  The  usual  process,  and  the  most  satisfactory  one  in  my  opin- 
ion, applicable  alike  to  small  or  large  amounts,  is  to  continue  the  per- 
colation with  water  after  the  extract  is  prepared,  and  recover  the  alcohol 
from  the  watery  runnings  by  distillation  ;  and  in  this  latter  percolation 
I  find  among  pharmacists  much  trouble  occasionally  is  experienced. 
If  the  materials  are  powdered  and  well  packed,  as  directed  by  the 
"  Pharmacopoeia,"  it  is  often  absolutely  impossible  to  percolate  with 
water  ;  the  ligneous  portion  of  the  mass  softens  and  swells  ;  the  gum, 
mucilage  and  extractive  matters  dissolve,  altogether  forming  a  glutinous 
paste  or  mush,  through  which  water  refuses  to  pass.  If  the  materials 
are  not  properly  powdered  and  packed,  the  extraction  of  the  medicinal 
principles  of  the  drug  is  found  to  be  difficult  or  impossible.  Conse- 
quently the  extract  is  likely  to  be  deficient  in  strength.  Less  trouble 
is  afterward  experienced  with  the  water  ;  but  mucilaginous  materials, 
like  buchu,  especially  such  as  have  been  exhausted  with  strong  alcohol, 
cannot  be  easily  percolated  with  water,  even  though  very  coarsely 
ground. 
I  find  it  advantageous  in  all  cases  to  have  the  exhausted  powder 
dumped  out  of  the  percolator  and  replaced  loosely.  I  have  a  set  of 
percolators  of  different  shape  expressly  for  residues,  and  require  every 
residue  to  be  removed  from  the  original  percolator.  But  this  will  not 
answer  for  some  articles,  as  it  seems  impossible  to  replace  them  loose 
enough.  To  overcome  the  trouble,  I  have  the  powders  of  certain 
materials  evenly  mixed  with  sawdust  as  soon  as  they  are  dumped. 
Buchu,  squills,  and  a  few  such,  require  about  their  own  bulk;  others, 
like  cimicifuga  and  aconite,  one-half  part.  Water  will  freely  permeate 
through  these  mixtures.  A  very  aggravating  trouble  is  overcome  by 
this  simple  process. 
Note  By  The  Editor. — When  working  with  large  quantities,  we 
-have  found  it  convenient  to  transfer  the  exhausted  powder  to  a  still 
and  inject  steam  under  pressure.    The  alcohol  distills  over,  gradually 
{  Am.  Jour.  Pharm. 
(       June,  1877, 
