PHARMACY  OF  THE  CINCHONAS. 
405 
ent  lots  of  all  the  higher  grades  of  Cinchona  vary  among  them- 
selves far  more  than  0*3  per  cent.  Therefore,  until  we  become 
more  critical  an  \  expert  in  the  selection  of  Cinchonas  in  the 
markets,  such  refinements  seem  superfluous,  and  may  be  safely 
postponed  to  a  more  advanced  stage  in  the  progress  of  phar- 
macy. 
"While  the  general  tendency  of  all  the  experiments  and  deduc- 
tions is  toward  Alcohol  as  the  best  menstruum  for  exhausting 
Cinchonas,  it  may  yet  be  safest,  in  view  of  the  previous  universal 
usage,  to  leave  the  question  still  open  for  farther  research  and 
confirmation,  accepting  the  results  here  given  only  so  far  as  to 
admit  that  Alcohol  is  a  good  menstruum,  and  capable  of  accom- 
plishing the  object  without  difficulty  or  disadvantage,  except 
from  its  greater'  cost.  This  much  being  taken  as  established, 
other  results  come  up  for  consideration. 
All  the  experiments  show  conclusively  that  Cinchona  is  much 
more  difficult  to  exhaust  than  was  heretofore  commonly  sup- 
posed ;  and  that  the  quantity  of  percolate  prescribed  by  the 
Pharmacopoeia  for  the  fluid  extract,  instead  of  being  excessive, 
as  was  believed  by  the  writer,  must,  under  any  ordinary  man- 
agement, with  good  Cinchona,  come  far  short  of  practical  ex- 
haustion, by  either  menstruum,  even  when  fine  powder  is  taken 
instead  of  the  "  moderately  fine,"  (50  meshes  to  the  inch,)  as 
directed.  Repeated  experiments  with  powder  that  passed  easily 
through  bolting  cloth  of  110  meshes  to  the  inch,  and  with  both 
menstrua,  showed  that  the  fifth  pint  of  percolate  contained  by  assay 
from  a  half  to  two  per  cent,  of  the  total  impure  alkaloids  in  the 
Cinchona.  The  officinal  quantity  of  percolate  cannot  therefore  be 
accepted  as  practically  sufficient  with  either  menstruum.  Nor 
is  the  prescribed  fineness  of  powder  well  adapted  to  economical 
exhaustion.  The  apparent  exhaustion  of  the  coarser  powder 
by  Diluted  Alcohol  must  have  been  judged  of  by  the  color  and 
taste  of  the  percolate,  and  is  apparent  only,  the  outside  of  the 
particles  being  only  imperfectly  washed  or  exhausted  by  the 
passing  menstruum.  With  fine  powder  and  the  same  menstruum 
the  color  and  taste  are  very  different. 
The  percolate  instead  of  being  "  evaporated  by  meams  of  a 
water  bath  "  should  with  either  menstruum  be  distilled,  and  the 
