334 
Flluid  Extracts. 
{Am.  Jour.  Pharm. 
July,  1878. 
menstruum,  and  when  the  percolate  appears  in  the  cotton  plug  at  the 
orifice  close  the  percolator  and  macerate  48  hours,  then  allow  the  per- 
colation to  proceed  until  75  parts  of  percolate  have  been  obtained, 
which  set  aside,  and  continue  the  percolation  until  the  senna  is 
exhausted  ;  evaporate  this  percolate  by  means  of  a  water-bath  to  25 
parts,  and  mix  it  with  the  reserved  portion. 
Wishing  to  ascertain  the  value  of  the  use  of  glycerin  in  fluid  extract 
of  senna,  three  fluid  extracts  were  prepared,  differing  only  from  the 
above  in  containing  respectively  10,  15  and  25  per  cent,  of  glycerin, 
which  was  added  to  the  dilute  percolates  previous  to  evaporation.  For 
that  sample  containing  25  per  cent,  of  glycerin  only  60  parts  of  percolate 
were  reserved.  Too  short  a  period  has  elapsed  since  their  preparation 
to  justify  an  opinion  as  to  the  effect  of  time  on  these  samples,  but  at 
present  my  belief  is  that  glycerin  is  of  no  service  in  fluid  extract  of 
senna. 
In  regard  to  repercolation,  it  is  probable  that  the  additional  labor  and 
trouble  of  the  several  packings  and  percolations  required  by  that  process 
may  be  quite  equaled  by  the  labor  and  trouble  of  evaporation  required 
by  the  process  of  simple  percolation  ;  the  remaining  dilute  percolate 
may  also  represent  what  usually  disappears  into  the  air  during  evapora- 
tion in  simple  percolation.  If  some  modification  of  the  process  of  reper- 
colation could  be  made  which  would  do  away  with  the  necessity  of  any 
dilute  percolate  remaining  over,  I  have  no  doubt  about  its  greatly  con- 
tributing to  the  general  adoption  of  that  process.  Having  no  practical 
experience  with  repercolation,  I  am  reluctant  to  suggest  a  modification 
of  it,  but  it  appears  to  me  that  if  100  parts  of  drug  were  taken  and 
divided  into  three  equal  portions,  and  25  parts  of  reserve  percolate 
obtained  from  each  of  the  first  two  portions  and  50  parts  from  the 
remaining  portion,  and  then  stop,  a  near  approach  to  at  least  practical 
exhaustion  would  be  made.  There  would  certainly  be  some  loss,  but 
as  the  50  parts  of  final  percolate  would  be  obtained  from  33J  parts  of 
drug  that  loss  could  not  seriously  affect  the  activity  of  the  preparation. 
I  hope  that  in  the  next  U.  S.  Pharmacopoeia  both  processes  may  be 
made  officinal,  thereby  allowing  pharmacists  to  use  whichever  they 
may  prefer. 
Philadelphia,  June  17th,  1878. 
