434  United  States  Pharmacopoeia. 
in  a  warm  place  for  forty-eight  hours.  While  the  petrolatum  may 
soften  the  powdered  beetles,  it  is  but  a  poor  solvent  for  the  active 
principle  and  the  combined  cantharidin  is  not  liberated. 
A  more  effective  preparation  is  secured  by  macerating  the  can- 
tharides  with  20  c.c.  acetic  acid  for  twenty-four  hours,  prior  to  adding 
it  to  the  resin,  yellow  wax,  lard  and  liquid  petrolatum,  previously 
melted  together  and  strained  through  muslin.  The  small  amount  of 
acetic  acid  remaining  in  the  finished  product  is  no  detriment  but 
rather  an  aid  to  its  action,  and  the  increase  in  weight  therefrom 
hardly  counterbalances  the  loss  sustained  in  straining  the  melted 
base. 
Extracts. — The  method'  of  preparing  the  solid  extracts  by 
evaporation  of  the  fluid  extracts,  which  is  officially  directed  in 
many  of  the  extracts,  does  not  appeal  to  the  manufacturer,  as  it  is 
wasteful  of  alcohol,  and  to  the  retailer  the  cost  would  be  greatly  in 
excess  of  the  purchase  price  of  a  satisfactory  article. 
This  method  likewise  exposes  the  active  constituent  of  the  drug 
to  the  prolonged  heating  of  both  the  original  preparation  of  fluid- 
extract  and  the  evaporation  directed  in  the  preparation  of  the  solid 
extract.  I  would  recommend  that  this  method  be  discontinued 
except  as  an  emergency  method  by  the  pharmacist  and  the  Pharma- 
copoeia direct  in  each  formula  for  solid  extract  the  direct  extraction 
with  the  menstruum. 
With  powdered  extracts  the  writer  has  experienced  considerable 
difficulty  from  caking  and  solidifying,  and  believes  that  this  has  also 
been  a  serious  annoyance  to  the  larger  manufacturers.  This  appears 
to  occur  mostly  in  the  extracts,  such  as  extract  of  nux  vomica,  in 
which  milk  sugar  is  specifically  directed  as  the  diluent.  I  believe 
that  this  can  be  corrected  by  substituting  for  the  milk  sugar  as  a 
diluent  the  finely  powdered  and  dry  drug  or  the  dried  and  finely 
powdered  marc  from  the  process.  In  the  introductory  notes  on 
page  52  of  the  Pharmacopoeia  "permission  is  given  to  employ  the 
dried  and  powdered  marc  from  the  percolation  of  the  same  drug  as 
a  diluent  in  place  of  powdered  peeled  Russian  licorice  root,"  and  it 
is  recommended  that  this  permission  be  extended  also  to  all  pow- 
dered extracts  in  which  milk  sugar  is  directed. 
While  the  Pharmacopoeia  does  in  this  revision  recognize  a  number 
of  powdered  extracts  the  list  should  be  extended  by  the  introduc- 
tion of  powdered  extracts  of  belladonna  leaves,  colchicum  corm, 
hyoscyamus  and  others  that  are  commonly  used  in  that  form. 
