ON  CAMPBELL'S  PROCESS  FOR  MAKING  FLUID  EXTRACTS.  119 
lowed  to  evaporate  to  the  consistence  of  honey.  Upon  exam- 
ination it  proved  to  contain  a  large  amount  of  glycerin,  together 
with  a  very  large  proportion  of  extractive  matter.  The  whole, 
when  concentrated  as  far  as  possible  with  the  means  at  my  dis- 
posal, weighed  no  less  than  5J  troyounces.  Allowing  one-half 
to  be  glycerin  it  would  leave  2f  troyounces  of  extract  not  dis- 
solved by  the  first  16  fluid-ounces  of  menstruum. 
In  order  to  demonstrate  whether  the  exhaust  contained  any 
virtues,  I  first  took  of  the  extract,  after  concentration,  f^  1 ; 
effect,  gentle  laxative.  Next  day  I  repeated  the  dose  and  in- 
creased it  at  the  same  time  to  f5  3 ;  result,  decidedly  cathartic* 
In  order  to  demonstrate  that  the  above  experiment  was  cor- 
rect, I  made  another  displacement  of  rhubarb.  The  results  were 
so  nearly  identical  that  it  confirmed  me  as  to  the  impracticability 
of  the  process. 
Similar  experiments  were  made  with  valerian  and  cinchona 
rub.,  botli  of  which  have  proven  that,  no  matter  how  long  the 
maceration,  or  how  slow  the  displacement,  it  is  impossible  to 
fully  obtain  all  the  active  matter  of  a  drug  in  16  fj  of  percolate. 
Although  admitting  that  when  the  percolation  is  properly 
conducted,  and  the  nature  of  the  drug  well  understood  by  the 
parties  manipulating,  a  fluid  extract  can  be  obtained,  which  will 
very  nearly  represent  the  full  activity  of  the  drug,  without  sub- 
jecting it  to  ^he  injurious  eff"ects  of  heat  during  evaporation  ; 
still  the  product  is  not  what  it  is  represented  to  be,  and  is  not 
of  the  strength  directed  in  the  U.  S.  P.  Again,  the  difficulty 
and  amount  of  care  required  to  properly  conduct  the  process 
is  so  great,  that,  by  incompetent  hands,  and  often  even  by  those 
who  are  well  versed  in  the  system  of  percolation,  very  variable 
and  inferior  preparations  must  evidently  be  the  result. 
It  is  apparent  that,  in  order  to  make  Campbell's  process  prac- 
ticable, a  total  revision  of  the  Pharmacopoeia,  relating  to  the 
subject  of  fluid  extracts,  would  be  necessary  ;  if  a  fluidounce  of 
the  extract  were  made  to  represent  a  half  ounce  of  the  drug, 
there  is  no  doubt  but  that  this  system  would  become  very  useful 
*  Query. — Would  not  a  menstruum  composed  of  three-fourths  alcohol 
and  one-fourth  glycerin  dissolve  more  of  the  active  constituents  of  the 
drug? 
