PHARMACY  OF  THE  CINCHONAS.  409 
• 
enough  to  practically  exhaust  the  Cinchona,  and  that  the  watery 
percolation  is  entirely  useless.  The  total  extract  of  83,  158  grs. 
is  very  nice  and  doubtless  efficient,  but  in  keeping  becomes  hard, 
resinous  and  soluble  with  difficulty.  The  defects  of  this  process 
may  be  remedied  and  a  better  result  obtained  by  the  following 
formula : 
Take  of  Cinchona,  either  Red  or  Yellow,  in  fine  powder, 
sixteen  troyounces, 
Glycerin,  one  troyounce, 
Alcohol,  six  pints  and  ten  fluidounces, 
Water,  a  sufficient  quantity. 
Mix  the  Cinchona  with  thirty  fluidounces  of  the  Alcohol  by 
thoroughly  stirring  them  together  in  a  proper  vessel ;  cover  the 
vessel  and,  having  allowed  the  mixture  to  stand  half  an  hour, 
pour  it  into  a  glass  funnel  prepared  for  percolation.  Then  pour 
the  remainder  of  the  Alcohol  on  top  as  required,  and  follow  this 
with  water  until  the  percolate  becomes  cloudy  and  makes  a 
precipitate  in  the  receiving  vessel.  Then  distil  off  the  Alcohol 
from  the  percolate  by  means  of  a  water  bath,  and  stir  the  residue 
on  the  water  bath  until  it  becomes  a  thick  extract  weighing  four 
troyounces.  To  this  add  the  Glycerin  and  heat  the  mixture 
with  stirring  until  a  perfectly  uniform  mixture  is  obtained 
weighing  not  more  than  five  troyounces.  Each  grain  of  this 
extract  represents  a  little  more  than  three  grains  of  the  Cinchona. 
The  Red  Cinchona  may  be  substituted  for  the  Yellow  in  this 
formula  when  desired,  the  management  required  being  the  same 
for  both. 
The  extract  of  Yellow  Cinchona  is  more  antiperiodic  and  less 
astringent.  That  from  Red  Cinchona  perhaps  more  purely 
tonic  and  more  astringent. 
In  working  the  above  formula  successfully,  the  powder  should 
be  very  fine — the  finer  the  better — and  the  Alcohol  of  full  offi- 
cinal strength  (s.  g.  *835.)  After  many  trials  with  various  pro- 
portions of  Alcohol  to  moisten  the  powder,  it  was  found  that 
almost  equally  good  results  were  obtained  with  all  reasonable 
proportions  after  a  moderate  experience  and  skill  were  acquired 
in  arranging  and  packing  the  percolator,  but  that  the  results 
were  so  much  improved  by  education  and  skill  that  it  was  de- 
