I 
2  ALCOHOL  IN  PHARMACY. 
effectually,  whilst  much  of  what  is  used  may  be  recovered  by  dis- 
tillation. 
To  make  a  pint  of  a  Fluid  Extract,  a  quart  of  alcohol  in  the 
shape  of  diluted  alcohol  is  required,  and  often  much  more  is  used. 
As  many  apothecaries  have  no  facilities  for  recovering  alcohol  by 
distillation,  this  must,  in  these  cases,  be  added  in  full  to  the  cost 
of  the  preparations. 
It  is  believed  that,  in  most  instances,  where  alcohol  is  merely 
used  as  a  solvent,  it  may  be  partially  recovered  by  distillation 
without  serious  injury  to  the  preparations,  but  the  particular  ob- 
ject of  this  paper  is  to  direct  attention  to  the  importance  of  econo- 
mizing in  the  use  of  alcohol  by  a  more  skilful  conduction  of  the 
process  of  percolation,  using  more  time  and  less  alcohol,  so  as  to 
get  an  equal  quantity  of  dissolved  matter  with  a  smaller  amount 
of  solvent.  This  is  entirely  practicable  in  most  instances  by  the 
use  of  uniformly  fine  powders,  (with  a  few  exceptions),  and  by 
regulating  the  flow  from  the  percolator  so  that  the  fluid  shall  have 
time  to  exert  its  maximum  solvent  power. 
The  directions  in  the  new  Pharmacopoeia,  in  the  preliminary 
chapter  on  percolation  and  powders,  are  so  explicit  and  full  that 
the  reader  should  be  at  no  loss  to  understand  them.  Failure,  if 
it  occur,  must  therefore  arise  from  neglect  of  these  precautions. 
Let  us  take,  for  example,  Fluid  Extract  of  wild  cherry  bark  : — 
Sixteen  troy  ounces  of  powdered  bark  are  to  be  extracted  by 
means  of  ordinary  alcohol,  (sp.  grs.  *835),  and  the  alcohol  is  after- 
wards to  be  wholly  separated  from  the  extracted  matter.  If  ii  fine 
powder  is  used  as  directed,  duly  moistened  with  a  fourth  of  its 
weight  of  alcohol,  and  then  compressed  in  the  percolator,  the 
fluid  will  pass  slowly  and  almost  like  syrup  in  consistence  at  first, 
and  long  before  the  quantity  directed  in  the  Pharmacopoeia  has 
passed,  the  bark  will  have  been  nearly  exhausted.  This  should 
be  set  aside  and  water  containing  a  little  alcohol  added  to  the 
percolator  to  displace  the  absorbed  alcohol,  until  the  liquid  passes 
cloudy,  when  the  process  may  be  stopped.  Now,  by  resorting  to 
a  still  heated  by  a  water  bath,  as  recommended  at  page  18  and  page 
22  the  alcohol  may  be  recovered  almost  entirely. 
These  remarks  apply  to  the  fluid  extracts  of  Ipecacuanha,  Sarsa- 
