22 
EXTRACTUM  PRUNI  VIRGINIANS  FLUIDUM. 
cane  sugar,  requiring  six  parts  of  that  liquid  to  dissolve  it,  hence 
each  dose  contains  less  than  ten  grains  of  the  sugar.  It  does 
not  undergo  the  vinous  fermentation  until  converted  into  grape 
sugar,  and  any  tendency  to  enter  the  lactic  fermentation  is  con- 
trolled by  the  hydrocyanic  acid  present. 
In  making  this  fluid  extract,  advantage  is  taken  of  the  fact 
that  alcohol  will  extract  the  amygdalin  (the  source  of  the  hydro- 
cyanic acid)  from  the  bark  without  touching  the  agent  which 
effects  its  decomposition  in  the  presence  of  water,  and,  at  the 
same  time,  removes  the  tannin,  and  the  bitter  principle  on  which 
its  tonic  power  mainly  depends.  To  insure  the  subsequent  de- 
composition of  the  amygdalin,  resort  is  had  to  theemulsin  of  sweet 
almonds,  which,  owing  to  its  solubility  in  water,  is  much  more 
manageable  than  the  insoluble  bark  residue.  The  following  is 
the  formula  : — 
Fluid  Extract  of  Wild  Cherry  Bark, 
Take  of  Wild  Cherry  bark,  in  powder,  24  ounces.  (Troy.) 
Sweet  almonds       .  .  3      "  " 
Lactine,  or  sugar  of  milk,  in  powder  8      "  " 
Alcohol,  (88  percent.) 
Water,  each  a  sufficient  quantity. 
Macerate  the  wild  cherry  bark  in  a  pint  and  a  half  of  alcohol 
for  eight  hours,  introduce  it  into  a  percolator  and  gradually  pour 
on  alcohol,  until  five  pints  of  tincture  have  passed,  observing  to 
regulate  the  passage  of  the  liquid  by  a  cork  or  stop  cock.  Intro- 
duce the  tincture  into  a  capsule  (or  distillatory  apparatus  if  the 
alcohol  is  to  be  regained),  and  evaporate  it  to  a  syrupy  consist- 
ence, add  half  a  pint  of  water,  and  again  evaporate  until  the  alco- 
hol is  entirely  removed.  Beat  the  almonds,  without  blanching, 
into  a  smooth  paste  with  a  little  of  the  water,  and  then  add  suffi- 
cient to  make  the  mixture  measure  two  pints  :  add  this  to  the  so- 
lution of  the  bark,  and  introduce  the  mixture  into  a  quart  bottle, 
cork  it,  and  allow  it  to  stand  twenty-four  hours,  with  occasional 
agitation  ;  then  quickly  express  in  a  close  cloth,  and  filter  into 
a  bottle  containing  the  lactine  in  powder.  Then  wash  the  dregs 
with  more  water,  until  sufficient  has  passed  to  make  the  filtered 
liquid  and  sugar  measure  three  pints ;  lastly,  dissolve  the  latter 
by  agitation  or  a  gentle  heat,  and  preserve  the  extract  in  closely 
stopped  bottles. 
