Am.  Jour.  Pharm.  \ 
March,  1897.  J 
Identifying  Fats  and  Oils. 
147 
Mitchell  and  Hehner  added  the  bromine  directly  to  the  oil,  but 
the  difficulty  of  conveniently  handling  I  c.c.  of  it  was  recognized 
by  Dr.  Wiley  (Journal  American  Chemical  Society \  April,  1896), 
who  suggested  that  it  be  diluted  with  chloroform. 
Acting  upon  his  suggestion,  we  diluted  in  the  proportion  of  1  c.c. 
of  bromine  to  4  c.c.  of  chloroform. 
The  action  of  the  bromine  on  some  of  the  oils  being  so  violent, 
we  diluted  or  dissolved  them  in  chloroform  in  the  proportion  of  6 
grammes  of  oil  and  made  up  to  30  c.c.  with  chloroform.  We  made 
up  this  quantity,  so  that  we  might  conduct  a  number  of  determina- 
tions on  each  oil  without  having  to  prepare  a  fresh  solution  for  each 
determination. 
Fig.  2. 
Of  the  chloroform  bromine  solution,  we  made  up  enough  to  last  for 
one  day's  work,  fearing  that  the  action  of  the  bromine  on  the  chlo- 
roform might,  in  due  time,  generate  hydrobromic  acid,  which  would 
interfere  with  the  results. 
It  is  of  great  importance  to  accurately  measure  the  5  c.c.  of  oil 
solution ;  this  is  best  accomplished  by  using  a  glass-stopped  burette, 
care  being  taken  to  avoid  any  loss  by  contact  with  the  walls  of  the 
tube  during  the  flowing  in. 
In  the  oil  solution  a  thermometer  is  inserted,  to  see  that  it  has 
the  same  temperature  as  the  bromine  solution  ;  if  such  is  not  the 
