Am.  Jour.  Pharna. 
July,  1893. 
Decomposition  of  Chloroform. 
357 
feeble  intensity  occur.  Consequently  the  effects  produced  will  vary, 
and  chloroform  which  in  one  experiment  is  found  to  show  decom- 
position within  two  hours  may  at  another  time  require  to  be  exposed 
for  a  whole  day  to  full  sunlight  before  it  shows  the  first  signs  of 
decomposition.  The  disappointment  arising  from  frequent  failure 
to  arrive  at  definite  results  from  such  experiments  may  be  attributed 
either  to  the  underrating  of  these  differences  in  the  chemical  activity  of 
sunlight  or  to  the  circumstance  that  the  influence  of  even  the  most 
minute  proportion  of  alcohol  is  disregarded.  If  the  investigators 
of  the  Pictet  chloroform  had  paid  attention  to  the  presence  of 
minute  traces  of  alcohol,  or  had  they  been  aware  of  the  importance 
to  be  attached  to  them  and  the  means  for  their  detection,  they 
would  have  avoided  the  disproof  of  their  statement  as  to  the  excep- 
tional durability  of  the  Pictet  chloroform.  From  the  first  announce- 
ment that  this  chloroform  had  been  experimentally  proved  to 
possess  a  capability  of  resisting  the  influence  of  sunlight  for  four 
days  we  drew  the  conclusion  that  it  contained  alcohol,  and  our 
prediction  that  such  was  the  case,  without  even  having  seen  a  sample, 
ultimately  proved  to  be  correct. 
Mr.  Brown's  statements  as  to  the  nature  of  the  products  of  the 
decomposition  of  chloroform  are  quite  correct.  These  products  may 
be  easily  recognized,  the  chloride  by  means  of  zinc  iodide  and 
starch,  the  carbon  oxychloride  by  its  peculiar  nauseous  smell, 
distinctly  different  from  that  of  chlorine.  If  it  be  needed  there  is  a 
much  better  mode  of  testing  for  carbon  oxychloride  than  by  the 
baryta  water  test  recommended  by  Professor  Ramsay,  viz  :  shaking 
the  decomposed  chloroform  with  mercury,  which  immediately  com- 
bines with  the  free  chlorine,  but  does  not  act  upon  the  carbon 
oxychloride,  and  thus  the  peculiar  smell  of  this  body  becomes  more 
easily  recognizable.  The  presence  of  free  chlorine  is  sufficiently 
indicated  by  the  coloration  of  moistened  test  paper  charged  with 
zinc  iodide  and  starch  when  it  is  immersed  in  the  atmosphere  of  the 
bottle,  also  by  the  bleaching  of  moistened  litmus  paper.  After  the 
removal  of  free  chlorine  by  agitation  with  mercury,  litmus  paper  is 
no  longer  bleached,  but  is  then  reddened,  since  the  water  in  the 
paper  determines  decomposition  of  carbon  oxychloride  with  pro- 
duction of  hydrochloric  acid  and  carbonic  anhydride.  Before  the 
removal  of  the  free  chlorine  this  reddening  of  moistened  litmus 
paper  is  masked  by  the  bleaching  action  of  the  free  chlorine. 
