TEST  FOR  ALCOHOL  IN  CHLOROFORM. 
213 
TEST  FOR  THE  PRESENCE  OF  ALCOHOL  IN  CHLOROFORM. 
By  William  Procter,  Jr. 
Being  recently  engaged  in  some  experiments  for  Prof.  Wood, 
on  the  solubility  of  chloroform  in  water,  with  and  without  the 
aid  of  alcohol,  I  was  struck  with  the  greater  solubility  of  that 
substance  than  the  books  admitted,  when  it  was  suggested  that 
the  chloroform  might  be  impure.  To  ascertain  this,  its  specific 
gravity  was  taken  with  great  care,  and  found  to  be  but  1.482. 
Suspecting  alcohol  to  be  present  as  the  cause  of  this  levity,  it 
occurred  to  me  that  an  oxidizing  mixture  of  bi-chromate  of  potassa 
and  sulphuric  acid  would  indicate  its  presence  without  being 
interfered  with  by  the  chloroform.  When  a  portion  of  the  sus- 
pected chloroform  was  added  to  the  deep  orange  colored  sulpho- 
chromic  mixture,  the  color  soon  changed  and  gradually  became 
green  from  the  formation  of  sulphate  of  chromic  oxide.  Another 
portion  of  the  chloroform  was  then  mixed  with  an  equal  bulk  of 
concentrated  sulphuric  acid,  and  agitated  occasionally  for  several 
hours  ;  the  acid  gradually  becomes  discolored  and  brown.  When, 
now,  a  part  of  the  supernatant  chloroform  was  added  to  the 
sulpho-chromic  mixture,  no  change  occurred  after  standing  a 
week. 
As  this  chloroform,  which  was  made  in  Philadelphia,  had  prob- 
ably been  washed  in  water,  it  follows  that  mere  aqueous  treat- 
ment will  not  remove  the  last  portions  of  alcohol,  and  that  agi- 
tation with  chloride  of  calcium  or  sulphuric  acid  is  necessary  to 
effect  its  abstraction.  The  latter,  however,  as  recommended  by 
Gregory  is  objectionable  as  giving  a  tendency  to  the  chloroform 
to  eliminate  chlorine. 
For  medical  use,  however,  the  small  percentage  of  alcohol 
present  is  perhaps  of  no  account,  and  it  is  probable  that  the 
larger  part  of  the  commercial  chloroform  is  less  contaminated  than 
the  specimen  tested.  As  corroborative  of  this  reaction  it  may 
be  observed  that  Dr.  Plummer,  of  Indiana,  in  experimenting 
with  the  sulpho-chromic  mixture  on  volatile  oils,  noticed  that  it 
was  colored  green  by  chloroform,  which  he  believed  was  due  to 
that  body,  whilst  in  reality  it  was  the  alcohol  contained  in  it. 
