PHARMACY  OF  THE  CINCHONAS. 
This  percolation  occupies  about  forty-eight  hours,  but  requires 
little  or  no  attention  if  the  funnel  and  receivers  be  large  enough. 
A  very  considerable  economy  in  alcohol  may  be  effected  when 
larger  quantities  of  Cinchona  are  percolated,  by  a  method  called 
by  the  writer  Repercplation.  This  consists  in  percolating  one 
portion  of  the  powder  with  the  percolate  from  a  previous  portion. 
This  method  will  be  briefly  described  in  some  of  the  formulas  of 
this  paper;  but  for  a  detailed  description,  and  the  interesting 
results  of  some  experiments  and  much  practice,  reference  must 
be  made  to  a  paper  to  be  presented  at  the  approaching  annual 
meeting  of  the  American  Pharmaceutical  Association.  The  pa- 
per is  entitled,  "  Itepercolation  applied  to  the  Cinchonas,  as  a 
method  of  economizing  Alcohol  in  the  exhaustion  of  drugs." 
In  order  to  recover  the  alcohol  from  the  percolate,  a  small 
water-bath  still  and  condenser  is  necessary."  One  the  inner 
vessel  of  which  holds  4  pints,  is  very  convenient,  but  that  used 
by  the  writer  for  many  years  past  holds  only  two  pints,  and  is 
quickly  and  easily  managed  over  a  small  table  gas  burner.  The 
weight  of  this  vessel  should  be  indelibly  scratched  on  it.  From 
the  6  pints  of  percolate  5  pints  4  f^  is  usually  recovered  before 
the  dropping  becomes  too  slow  to  compensate  the  time  and  fuel, 
and  the  alcohol  so  recovered  is  of  a  proper  strength  to  be  used 
at  once  for  a  fresh  portion  of  Cinchona.  The  Cinchona  odor, 
however,  unfits  it  for  most  other  uses.  The  head  of  the  still  is 
then  removed,  and  a  weighed  stirrer,  with  a  somewhat  broad 
flattened  end,  introduced.  The  thin  rich-looking  liquid  extract 
usually  measures  about  4J  to  5  f£.  when  the  head  is  removed, 
and  this,  by  about  ten  minutes'  active  stirring  on  the  bath,  is 
easily  reduced  to  four  troyounces.  The  shape  of  the  end  of  the 
stirrer  has  very  much  to  do  with  the  rapidity  and  facility  of  this 
part  of  the  process,  and  if  a  rod  be  used,  the  time  required  is 
much  longer.,  The  weight  of  the  still  and  stirrer  being  known, 
it  is  easy  from  time  to  time  to  set  the  vessel  on  a  scale  until  the 
proper  weight,  or  near  it,  is  attained.  The  troy  ounce  of  Glyce- 
rin is  most  conveniently  added  while  the  vessel  is  sitting  on  the 
scale,  care  being  taken  not  to  pour  in  too  much.  The  vessel  is 
then  replaced  in  the  water-bath,  and  heated  until  the  Glycerin 
becomes  sufficiently  hot  and  fluid  to  dissolve  the  extract,  and  the 
