^™  ASgusri9'2a}      U.  S.  Pharmacopoeial  Revision.  559 
Add  the  light  magnesium  oxide  gradually  and  with  constant 
stirring  to  800  Mils  of  the  solution  of  calcium  hydroxide,  contained 
in  a  graduated  jar  of  at  least  double  the  capacity  required  for  the 
mixture.  Then  add  enough  of  the  solution  of  calcium  hydroxide 
to  make  the  product  measure  1000  Mils  and  shake  or  stir  the  mixture 
vigorously  at  frequent  intervals  until  it  has  thickened  properly. 
Mistura  Cretae. — ^This  mixture  can  be  prepared  so  that  it  is 
permanent  and  ready  for  instant  dispensing,  as  follows: 
Add  I  Mil  of  oil  of  cinnamon  to  200  Gms.  of  compound  chalk  pow- 
der. Gradually  and  thoroughly  triturate  this  powder  with  400  Mils 
of  cinnamon  water.  Transfer  the  mixture  to  a  graduated  bottle 
and  add  sufficient  cinnamon  water  to  riiake  the  product  measure 
1000  Mils.  The  preparation  of  this  mixture  before  actually  needed 
usually  assures  a  more  perfect  suspension  of  the  chalk,  due  to  more 
careful  trituration.  The  added  oil  preserves  the  mixture  indefinitely 
and  increases  its  palatability.  The  mixture  is  ready  for  instant 
dispensing  and  will  not  ferment  within  a  few  hours  when  kept  by 
the  patient,  as  frequently  occurs  when  the  official  mixture  is  dis- 
pensed. This  new  formula  has  been  tried  under  all  manner  of 
store  conditions  and  temperatures,  and  has  been  found  to  keep  in- 
definitely. 
Mucilago  Acaciae. — It  is  suggested  that  the  official  mucilage  be 
made  extemporaneously  from  granulated  acacia.  This  is  the  almost 
universal  custom  and  if  a  granulated  acacia  is  selected,  of  official 
quality,  the  product  is  entirely  satisfactory. 
Oleoresins. — The  Pharmacopoeia  has  alternated  on  the  solvent 
used  for  oleoresins  in  each  of  the  recent  revisions.  In  one  decade 
it  was  acetone,  in  the  next,  ether,  for  all  of  the  oleoresins  except 
cubeb.  It  is  suggested  that  either  solvent  be  directed,  except  in 
oleoresin  of  cubeb,  as  they  seem  to  be  identical  in  action.  This  will 
permit  the  use  of  the  one  which  is  readily  obtainable  or  the  one 
which  is  most  economica.1. 
Oleum  Aurantii  and  Oleum  Limonis. — The  addition  of  5  per  cent, 
of  a  fixed  oil,  preferably  olive  oil,  to  these  citrus  oils,  has  been  found 
to  preserve  them  indefinitely  from  the  development  of  turpentine- 
odor.  There  would  be  no  serious  objection  to  the  Pharmacopoeia 
recognizing  this  method  of  preservation,  as  it  would  mean  the  use 
of  oils  of  satisfactory  quality  in  elixirs  and  elsewhere,  instead  of  the 
frequent  employment  of  oils  having  a  turpentine-like  odor.  The 
added  olive  oil  would  separate  from  most  of  the  mixtures  and  could 
