i94 
Salicylic  Acid  in  Food. 
Am.  Jour.  Pharm. 
April,  1894. 
which  has  been  most  commonly  used  involves  the  separation  of  the 
salicylic  acid  by  distillation  with  water  vapor.  The  use  of  distillation 
for  this  purpose,  separating  salicylic  acid  from  food,  I  believe  was  first 
proposed  in  an  unsigned  article  appearing  in  the  Chemiker  Zeitung,  in 
1882,  presumably  from  the  pen  of  the  editor,  G.  Krause.  It  was  there 
stated  that  the  method  had  been  elaborated  in  the  laboratory  of  that 
paper.  Kolbe  used  distillation  for  the  analytical  separation  of  salicylic 
acid  in  1880.  In  using  it  in  this  laboratory  on  the  samples  of  canned 
vegetables,  the  analyses  of  which  are  recorded  in  Bulletin  13,  part 
8,  of  the  Division  of  Chemistry,  United  States  Department  of  Agri- 
culture, the  contents  of  the  can  were  pulped  in  a  mortar,  water 
added,  together  with  a  little  phosphoric  acid,  the  mixture  strained 
through  a  bag,  and  the  liquid  subjected  to  distillation.  The  distil- 
late was  then  collected  in  small  portions,  and  each  portion  separately 
tested  with  iron  chloride.  Mr.  W.  D.  Bigelow,  who  was  associated 
with  me  in  the  analyses  of  these  goods,  and  who  made  the  greater 
portion  of  the  tests,  found  the  best  strength  of  ferric  chloride  to  be 
about  five  mgms.  to  the  cc.  The  salicylic  acid  has  a  tendency  to 
accumulate  in  the  later  portions  of  the  distillate,  and  where  the 
amount  present  is  small,  there  will  be  hardly  any  test  given  by  the 
first  fractions.  In  illustration  of  this  the  following  experiment  may 
be  adduced.  Twenty-five  milligrams'  of  the  salicylic  acid  were 
dissolved  in  250  cc.  of  water  containing  a  little  phosphoric  acid  and 
the  mixture  subjected  to  distillation,  the  distillate  being  collected 
in  twenty-five  cc.  portions  and  the  salicylic  acid  estimated  colori- 
metrically.    The  results  may  be  tabulated  as  follows  : 
No.  CC.  Reaction.  Quantity  Found. 
1  25  Distinct  but  pale,  
2  25  Somewhat  stronger,  
3  25  Still  stronger,  0*3  mgm. 
5  25  Bright,  0-5 
6  25  "   o-8 
8  25  "      •  2'2  mgms. 
9  15  "   3*o  " 
Total,   .  8*i  mgms. 
I  will  quote  in  further  illustration  of  this  tendency  the  method 
for  the  determination  of  salicylic  acid  in  wine  described  by  M.  Ince. 
In  this  method  210  cc.  of  wine  are  mixed  with  ten  cc.  of  dilute  sul- 
