74  SPECIFIC  GRAVITY  OF  MEDICINAL  CHLOROFORM. 
chloroform  might  cause  its  rapid  decomposition.  Some  was 
rectified  from  a  very  carefully-regulated  water  bath,  and  it  was 
again  observed  that  98  per  cent,  may  be  obtained  in  this  way  of 
such  a  purity  that  sulphuric  acid  will  not  be  affected  in  the  least. 
This  perfectly  clean  chloroform  generated  free  chlorine  quite 
as  rapidly  as  before  ;  if  diluted  with  alcohol  to  below  1*480,  it 
was  unaffected  by  the  light. 
Mr.  Augustus  Henkel,  now  of  Cincinnati,  and,  for  a  time,  one 
of  my  valuable  assistants  at  the  Laboratory,  made  a  series  of 
experiments  on  the  effects  of  light,  the  results  of  which  I  sub- 
join herewith.  The  chloroform  used  for  the  experiments  had  a 
specific  gravity  of  1*492  at  70°  F.,  was  absolutely  free  from  acid 
reaction,  and  imparted  no  coloration  whatever  to  sulphuric  acid. 
The  diluted  chloroform  was  made  of  eight  ounces  of  the  former, 
by  the  addition  of  one  fluidrachm  of  strong  alcohol.  The  bottles 
used  for  the  occasion  were  made  of  flint  glass,  of  uniform  size 
and  shape,  and  filled  alike.  The  experiments  lasted  one  week 
during  the  hot  days  in  August,  1865. 
1.  Experiments  with  pure  chloroform. 
Appearance  and  reaction  of  chloroform  at  the  end  of  the  week,  when  kept 
a.  In  the  dark.  6.  In  daylight         c.  In  direct  sunlight. 
Bote,  glass-stop'd.    Extremely  slight  reaction.     Decidedly  acid.  I  Free  chlorine  in  yellow  drops 
e  *        J       and  suffocating  odor. 
i(   corked.  «  "         "  Slightly  acid. 
Cans  soldered.         Unchanged.  Unaltered.  Unaltered. 
"    corked.  Hardly  recognizable.  "  " 
2.  Experiments  with  diluted  chloroform. 
Appearance  and  reaction  at  the  end  of  a  week  when  kept 
a.  In  the  dark.  b.  In  diffused  daylight.  c.  In  direct  sunlight. 
Bottles  glass  stoppered.    Unchanged.                     Unchanged.  Unchanged. 
"     corked.  "  "  " 
Cans  soldered.  "  "  " 
"    corked.  "  "  " 
It  was  concluded  from  these  experiments  : — 
1.  That  in  order  to  preserve  pure  chloroform  of  specific 
gravity  1*49,  it  should  be  kept  totally  excluded  from  the  light. 
2.  That  to  keep  chloroform  in  the  daylight,  it  should  be 
reduced  in  specific  gravity  by  the  addition  of  about  two  flui- 
drachms  of  95  per  cent,  alcohol  to  one  avoirdupois  pound  of 
chloroform,  sp.  gr.  1-492. 
During  the  repetition  of  some  of  these  experiments,  attention 
