ON  Campbell's  process  for  making  fluid  extracts.  117 
for  displacement,iwith  the  lower  end  closed  with  a  cork.  Pour 
on  the  contents  of  the  displacer  four  fluid-drachms  of  stronger 
ether  and  cover  it  with  an  accurately  fitting  plate  of  glass.  At 
the  expiration  of  twelve  hours  displace  with  a  mixture  of  stronger 
ether  and  stronger  alcohol  in  equal  measures  until  two  fluid- 
ounces  are  obtained,  which  set  aside  in  a  three  ounce  vial.  Con- 
tinue the  displacements  until  one  fluid-ounce  more  has  passed 
through.  Allow  this  to  evaporate  spontaneously  and  dissolve  it 
in  the  first  two  fluid-ounces  of  percolate  obtained,  to  which  add 
six  grains  of  collodion  cotton,  or  a  sufficient  quantity  to  make 
the  cantharidal  collodion  of  the  proper  consistence.  Agitate  the 
mixture  occasionally  until  the  cotton  is  dissolved. 
Baltijnore,  Md.,  February,  1870. 
ON  CAMPBELL'S  PROCESS  FOR  THE  MANUFACTURE  OF 
FLUID  EXTRACTS. 
By  Henry  C.  Archibald. 
Esteemed  Editor  — Feeling,  as  I  do,  a  lively  interest  in  all 
that  pertains  to  the  advancement  of  Pharmacy,  and  having  read 
with  interest  Mr.  Campbell's  process  for  the  manufacture  of 
fluid  extracts,  together  with  comments  thereon,  I  determined 
myself  to  apply  his  theory  of  percolation  (which,  by  the  way,  is 
an  old  one)  upon  a  few  drugs,  and  to  submit  for  inspection  my 
views  of  the  same.  We  all  know  that  what  is  most  wanted  in  a 
fluid  extract  is  that  the  active  constituents  of  the  drug  be  fully 
and  wholly  represented,  without,  or  at  least,  with  as  little  de- 
composable matter  as  possible,  at  the  same  time  to  have  a  men- 
struum of  uniform  strength,  capable  of  holding,  without  precipi- 
tation, the  active  matter  so  taken  up.  These  qualities,  with  but 
few  exceptions,  are  attainable  by  the  processes  of  the  U.  S.  P., 
which  afford  most  excellent  products.  In  order  to  determine 
whether  Campbell's  process  possessed  that  merit,  which  the  author 
claimed,  a  few  experiments  were  made,  with  the  following  re- 
sults : 
1st.  16  troyounces  of  Jamaica  ginger  of  the  requisite  fineness 
to  pass  through  a  No.  40  sieve,  were  moistened  with  f^4  of  a 
menstruum,  composed  of  alcohol  three-fourths  and  glycerin  one- 
