502 
Liquor  Potassii  Arsenitis. 
f  Am.  Jour.  Pharm, 
t      Oct.,  1877. 
a  few  minutes  the  cork  flew  out,  and  nearly  half  the  contents  were 
thrown  out.  Thinking  that  the  syrup  in  question  perhaps  had  become 
acid,  it  was  extemporized  with  powdered  gum  arabic  and  simple  syrup  \. 
again  an  explosion.  Simple  syrup  gave  a  similar  result,  and  a  trial  with 
only  distilled  water  went  no  better.  It  became  clear  now  that  the 
decomposition  of  the  salt  was  solely  due  to  the  high  temperature.  By 
using  half  ice  water  and  syrupus  acaciae  no  evolution  of  carbonic  acid 
gas  took  place. 
It  would  be  interesting  to  learn  whether  similar  mishaps  have  been 
experienced  by  other  pharmacists. 
The  question  arises,  whether  physicians  will  put  up  with  this,  quite 
unavoidable  loss  of  carbonic  acid  gas,  or  whether  they  can  forego  the 
use  of  carbonate  of  ammonium  in  summer  time.  One  thing  seems- 
certain,  that  concentrated  solutions  of  this  salt  have  to  be  made  and 
kept  with  ice.  (Concentrated  :  1  part  carbonate  of  ammonium  requires 
4  parts  water.) 
LIQUOR  POTASSII  ARSENITIS. 
By  John  C.  Wharton. 
In  some  of  the  old  editions  of  the  U.  S.  Pharmacopoeia  this  prepar- 
ation is  directed  to  be  made  by  dissolving  sixty-four  grains  each  of 
arsenious  acid  and  carbonate  of  potassium,  by  the  aid  of  heat,  in  twelve 
fluidounces  of  distilled  water,  and  after  solution  adding  half  a  fluidounce 
of  spirit  of  lavender  compound  and  sufficient  distilled  water  to  make 
the  cold  solution  measure  one  pint. 
In  the  last  edition  of  the  U.  S.  P.  the  formula  requires  that  bicarb- 
onate of  potassium  shall  be  substituted  for  the  carbonate  above  referred 
to,  and  to  effect  the  solution  of  the  arsenious  acid  and  bicarbonate  of 
potassium  bv  boiling  them  with  half  a  fluidounce  of  distilled  water,, 
then  adding  distilled  water  twelve  fluidounces,  compound  spirit  of 
lavender  half  a  fluidounce,  and  lastly  sufficient  distilled  water  to  make 
the  cold  solution  measure  one  pint. 
The  latter  formula  is  doubtless  better  than  the  former,  in  at  least 
two  particulars.  It  requires  no  excess  of  alkali,  in  fact  if  both  acid 
and  alkali  are  of  theoretical  purity,  there  is  a  deficiency  of  the  bicarb- 
onate of  potassium  to  the  amount  of  nearly  one  grain,  and  sixty-five 
grains  of  that  salt  would  be  the  proper  amount  to  be  used.  An  im- 
provement in  the  manipulation  is  made  by  the  use  of  only  half  a  fluid- 
