178  Color  in  Liquor  Calcis  Saccharratus.        { ^""'ApririsS*™' 
THE  DEVELOPMENT  OF  COLOE  IN  LIQUOR  CALCIS 
SACCHARATUS.^ 
By  John  R.  Hill. 
The  gradual  development  of  a  yellowish -brown  color  in  the  official 
liquor  calcis  saccharatus  attracted  my  attention  a  few  years  ago.  I  did 
not  at  that  time  attempt  to  ascertain  the  cause  of  the  phenomenon,  my 
inquiries  being  rather  directed  to  the  point  of  ascertaining  whether  or 
not  the  coloration  was  accompanied  by  any  deterioration  in  alkalinity. 
With  this  view  I  made  estimation  of  freshly  prepared  liquor  and  of 
the  same  after  being  allowed  to  stand  until  considerably  colored.  On 
comparing  the  two  results,  they  were  found  to  indicate  only  a  very 
slight  deficiency  in  the  colored  liquor.  It  was,  therefore,  concluded 
that,  practically  the  coloration  was  of  very  little  consequence. 
The  subject  was  again  brought  under  my  notice  recently  by  a  request 
to  furnish  au  answer  to  the  query,  What  causes  the  coloration  of  liquor 
calcis  saccharatus,  and  how  may  it  be  prevented?  Being  at  the  time 
engaged  in  the  preparation  of  our  usual  stock  quantity  of  the  liquor,  I 
embraced  the  op})ortuuity  of  making  a  few  observations. 
The  British  Pharmacopoeia  directs  the  clear  solution  to  be  decanted 
from  the  sediment ;  but  it  has  been  my  usual  practice  to  filter  off  after 
allowing  to  stimd  for  twelve  hours.  Following  the  latter  method,  the 
clear  liquid  which  passes  rapidly  through  the  filter  was  kept  separate. 
The  sedimentary  portion,  of  course,  filtered  more  slowl}^,  and  on  com- 
paring the  two  liquids  I  was  a  little  surprised  to  find  that  the  latter 
was  considerably  deeper  in  color — a  fact  which  is  explained  further  on. 
Squire  states  that  the  fresh  liquor  is  colorless,  but  gradually  acquires  a 
brownisii  color.  Neligan  states  that  it  is  transparent,  but  possesses  a 
slight  yellowish  tint.  The  latter  appears  to  be  the  more  correct  state- 
ment, my  experience  being  that  froui  the  first,  the  liquor  is  of  a  very 
pale  straw  color. 
In  attempting  to  answer  the  above  query,  the  first  thing  done  was  to 
ascertain  if  there  were  any  published  results  on  the  subject ;  but  a 
rapid  glance  through  all  the  availing  literature  goes  to  show  that  the 
point  has  not  been  previously  investigated.  A  series  of  experiments 
were  then  made  to  determine  the  respective  effects  of  the  three  agencies 
— light,  heat  and  exposure  to  the  atmosphere. 
1  Read  at  a  meeting  of  the  North  British  Branch  of  the  Pharmaceutical 
Society,  January  14,  1885. 
