AmM£y!\s87arm'}  Extr actum  Pruni  Virginiance  Fluidum  231 
EXTRACTUM  PRUNI  VIRGINIANS  FLUIDUM. 
By  Cyrus  M.  Bogee,  Ph.  G. 
Read  at  the  Pharmaceutical  Meeting  April  19,  1887. 
Perhaps  no  other  drug  in  the  pharmacopoeia  has  been  investigated 
as  much  and  written  upon  as  often  as  Wild  Cherry  Bark.  -. 
While  many  valuable  additions  have  from  time  to  time  been  made 
to  our  knowledge  concerning  it,  yet  its  preparations  remain  for  the 
most  part  unsatisfactory. 
The  design  of  this  paper  is  the  discussion  of  its  fluid-extract ;  the 
chief  objects  to  be  attained  in  making  this  are  : 
1.  To  develop  all  the  hydrocyanic  acid  the  bark  is  capable  of  yield- 
ing. 
2.  To  have  as  little  tannic  acid  present  when  finished  as  possible. 
3.  To  have  it  free  from  a  precipitate — The  U.  S.  Pharmacopoeia 
process  fulfils  none  of  these  requirements  ;  why  does  it  not  ? 
1.  Because  the  time  allowed  for  maceration  is  too  short. 
2.  The  addition  of  glycerin  hinders  the  development  of  prussic 
acid  during  maceration. 
3.  The  drug  is  not  moistened  sufficiently  to  develop  all  the  acid. 
Experience  has  proven  that  sixty  hours  at  least  must  be  allowed  for 
the  full  development  of  the  acid  and  that  seventy-two  hours  is  not 
too  long. 
The  viscidity  and  therefore  the  immobility  of  a  liquid  materially 
affects  the  rapidity  of  chemical  action  ;  the  advantage  to  be  gained  from 
the  addition  of  glycerin  to  the  macerate  is  therefore  not  apparent  and 
experience  has  shown  its  influence  to  be  inimical  in  this  process. 
The  hydrocyanic  acid  does  not  develop  well  when  the  bark  is  not 
moistened  sufficiently,  any  more  than  it  does  when  made  too  wet ;  ac- 
tual practice  has  shown  that  the  U.  S.  Pharmacopoeia  process  does  not 
allow  sufficent  moistening.  Just  here  it  may  be  remarked  that  after 
the  addition  of  the  macerate  the  bark  should  not  be  packed  at  all  but 
put  loosely  into  a  percolator  until  it  is  time  to  pack  it  for  the  perco- 
lation. 
The  matter  of  tannic  acid  has  puzzled  a  great  many  persons  and  it 
is  quite  enough  to  say  that  the  addition  of  a  large  quantity  of  glycer- 
in to  the  formula  has  not  reduced  the  amount  dissolved,  even  if  it  has 
helped  to  hold  it  in  solution  ;  seeing  that  the  acid  is  freely  soluble  in 
both  water  and  alcohol  there  is  little  hope  that  very  much  can  be  ac- 
