248         New  P)-ocess  for  Detecting  Bromide,  etc.  {A  jiS^jS?* 
dispensing  the  salts  of  morphia  (or  other  alkaloids)  with  iodide  or 
bromide  of  potassium  which  gives  an  alkaline  reaction ;  for  if  pre- 
scribed with  syrup,  as  in  the  above  prescription,  the  precipitated  mor- 
phia will  rise  to  the  surface  of  the  mixture,  and,  should  it  not  be 
"  shaken  before  taken,"  the  patient  will  be  liable  to  take  all,  or  nearly 
all,  the  morphine  in  the  mixture  at  a  single  dose. 
It  is  therefore  advisable  for  the  dispenser,  whenever  a  morphia  salt 
is  prescribed  with  iodide  or  bromide  of  potassium  in  solution,  to  first 
dissolve  the  latter,  test  the  solution  with  turmeric  or  red  litmus  paper, 
and  if  alkaline  neutralize  with  dilute  muriatic  acid  before  adding  the 
morphia  salt ;  and  a  bottle  of  the  acid  mentioned  and  the  necessary 
test  paper  should  be  placed  convenient  to  the  prescription  counter,  for 
this  if  for  no  other  purpose.* 
With  a  small  proportion  of  morphia  salt  the  precipitate  is  often  not 
observed  until  after  standing  a  short  time. 
St.  Louis,  April  18th,  1872. 
ON  A  NEW  PROCESS  FOR  DETECTING  BROMIDE  IN  IODIDE 
OF  POTASSIUM.! 
By  Edm.  Van  Melckebeke,  D.  Sc. 
The  proposed  process  is  based  upon  the  property  of  a  saturated 
solution  of  one  salt  to  dissolve  another  one,  provided  the  two  salts  do 
not  produce  a  precipitate  with  each  other.  If  to  a  saturated  solution 
of  bromide  of  potassium  a  small  quantity  of  pure  iodide  of  potassium 
is  added,  it  will  completely  dissolve ;  but  if  it  was  contaminated  with 
bromide  of  potassium,  this  impurity  will  remain  undissolved.  The 
quantity  of  iodide  dissolved  in  this  case  is  much  smaller  than  that 
soluble  in  the  same  volume  of  water  at  the  same  temperature.  This 
solubility  has  a  limit  which  cannot  be  exceeded  without  precipitating 
bromide,  caused  by  the  isomorphism  of  the  two  salts,  and  by  the  great 
difference  in  their  solubility. 
It  is  known  that  a  mixture  of  salts  which  are  not  isomorphous,  dis- 
solves always  to  a  greater  extent  in  water  than  either  salt  alone  under 
*  Commercial  iodide  of  potassium  is  usually  crystallized  from  alkaline  solu- 
tions in  order  to  obtain  it  in  opaque  cubes  ;  recrystallization  or  granulation 
from  water  will  effectually  remove  any  adhering  alkaline  carbonate. — Editor 
Amer.  Jour.  Pharm. 
f  Condensed  from  a  paper  read  before  the  Societe  de  Pharmacie  d'Anvers, 
and  communicated  by  the  author. 
