546 
FACILITIES  FOR  DISPENSING  MEDICINES. 
5.  Similar  mixtures  as  the  above  can  be  made  with  morphia, 
opium,  and  tartar  emetic.  The  proportions  may  be  made  the 
same,  or  smaller, 
6.  A  Concentrated  Solution  of  Gum  AraMc. — Instead  of  using 
the  powdered  gum  arabic  wherever  prescribed  in  liquids,  it  is 
better  to  use  a  solution  of  the  gum  in  proportion  1:2;  with 
this  the  medicine  will  always  look  nice  and  clean,  and  emulsions 
made  with  it  will  be  elegant. 
7.  In  a  good  many  instances  the  dispensing  druggists  will 
avoid  straining  mixtures,  by  keeping  solutions  in  the  proportion 
of  1  :  2  of  the  following  salts :  Ammonite  murias,  magnesia 
sulphas,  potassse  nitras,  soda  sulphis. 
8.  Very  practicable  are  solutions  of  several  narcotic  extracts, 
for  example  :  Extractum  hyoscyami,  extractum  'aconiti,  ex- 
tractum  belladonnae,  extractum  opii.  As  these  extracts  are  often 
used  in  ointments,  their  solutions  have  to  be  concentrated  1  :  2, 
and  as  they  are  liable  to  decompose  when  dissolved  in  water 
alone,  an  addition  of  alcohol  is  necessary ;  glycerin  is  also  a 
good  solvent  for  them. 
9.  Misturae  cretae  is  a  preparation  which  only  should  be  made 
extemporaneously.  For  this  purpose,  the  dry  mixture  may  be 
kept  ready  according  to  the  Pharmacopoeia,  i.  e. :  R  Cretae  prae- 
paratae,  two  parts ;  sacchari  albi ;  pulvis  acaciae  aa  one  part,  mix. 
One  drachm  of  this  with  half  an  ounce  each  of  water  and  cin- 
namon water  will  make  one  ounce  of  chalk  mixture. 
10.  We  can  not  always  get  fresh  lard,  and  as  long  as  our  un- 
guent um  simplex  is  directed  to  be  made  with  white  wax — an 
already  rancid  body — it  happens  very  often  that  an  ointment  of 
iodide  of  potassium  gets  yellow,  instead  of  being  perfectly  white. 
A  few  grains  of  hyposulphite  of  soda  dissolved  in  a  little jvater, 
added  to  such  ointment,  will  turn  it  snow  white; 
11.  Acetate  of  lead  will  change  partly  into  carbonate  of  lead 
by  the  carbonic  acid  of  the  atmosphere  or  of  the  water  ;  there- 
fore solutions  of  it  will  always  have  a  milky  appearance.  In  all 
cases  where  it  is  prescribed  for  internal  use,  the  precipitated 
carbonate  of  lead  should  be  redissolved  with  a  few  drops  of  acetic 
acid,  and  the  solution  will  be  clear. 
