396     PREPARATIONS  OP  THE  U.  S.  PHARMACOPOEIA,  1860. 
soluble  in  the  alcohol,  precipitates,  in  a  consistent  state,  owing 
to  the  abstraction  from  it  of  a  part  of  its  moisture  by  the  alcohol. 
After  24  hours  maceration  the  tincture  is  filtered,  the  dregs 
washed  with  alcohol,  and  the  liquid  evaporated.  The  probability 
is  that  nearly  all  the  extract  of  hemp  used  in  dispensing  is  the 
commercial.  We  have  not  seen  a  prescription  for  the  purified 
extract  as  yet ;  hence  the  inference  is  that  this  preparation  is 
mainly  intended  for  the  preparation  of  the  tincture.  If  this  be 
true  it  were  better  to  have  included  it  in  the  recipe  for  the  tinc- 
ture. I  am  not  aware  that  any  experiments  have  been  made  to 
ascertain  whether  the  matter  insoluble  in  alcohol  has  any  activity, 
but  presume  that  it  has  not,  and  to  this  extent  the  commercial 
extract  is  deficient  in  power,  yet  there  is  great  reason  to  believe 
that  all  the  merely  resinous  matter  of  the  commercial  extracts  is 
not  true  cannabin,  else  there  could  not  be  so  much  variation  as 
is  found. 
Extractum  Colocynthidis  Alcoholicum. — This  formula  may  be 
looked  upon  as  preliminary  and  auxiliary  to  that  for  the  com- 
pound extract  in  which  it  was  formerly  included.  The  process 
is  entirely  practicable,  and  furnishes  a  good  product  where  the 
drug  has  been  selected.  Forty-eight  troy  ounces  of  crude  colo- 
cynth,  and  two  gallons  of  diluted  alcohol  are  required.  The 
alcohol  is  nearly  all  recovered,  and  may  be  used  again.  The 
evaporation  is  continued  to  dryness  so  that  the  product  will 
powder,  in  which  state  it  is  directed  to  be  kept,  and  amounts  to 
about  one-seventh  of  the  colocynth  employed  to  make  it. 
Ext.  Colocynth.  Comp. — This  formula  has  been  modified  nearly 
as  prepared  by  Dr.  Squibb,  (see  Amer.  Jour.  Pharm.,  vol.  v.  97), 
which  composition  is  based  upon  an  analysis  of  the  ingredients, 
as  to  the  dry  product  of  each  as  contained  in  the  dried  extract ; 
by  then  using  each  ingredient  in  powder  the  uniformity  of  this 
very  important  preparation  may  always  be  controlled.  By  sub- 
stituting resin  of  scammony  for  the  scammony,  a  check  is  given 
to  avoid  the  adulterated  scammony  of  commerce,  and  the  genu- 
ineness of  scammony  resin  may  be  easily  determined  by  chemical 
and  physical  tests. 
The  satisfaction  attending  the  use  of  this  form  of  the  extract 
