3o8 
Study  of  Fruit  and  Vegetable  Colors.  { 
Am.  Jour.  Pharm. 
July,  1905. 
was  produced  upon  the  addition  of  ammonium  hydroxide  solution 
to  the  dyed  wool. 
These  differences,  when  carefully  studied,  will  be  found  to  afford 
a  means  of  differentiating  many  of  the  vegetable  colors  and  of  abso- 
lutely proving  the  presence  of  synthetic  colors. 
Fuller's  earth,  kaolin  and  kindred  earthy  materials  have  been 
observed  to  have  the  property  of  removing  certain  colors  from  their 
aqueous  solutions,  and  one  of  the  tests  for  the  presence  of  caramel 
is  based  upon  this  color-absorbing  property  of  fuller's  earth. 
A  sample  of  kaolin  was  obtained  which  gave  excellent  results 
when  used  in  the  caramel  test,  and  a  test  was  made  upon  each  of 
the  color  solutions  and  the  effect  noted. 
Twenty-five  cubic  centimeters  of  the  color  solution  were  agitated 
for  five  minutes  with  10  grammes  of  the  kaolin,  the  mixture  was 
poured  upon  a  dry  plaited  filter  and  the  filtrate  collected  in  a  dry 
Nessler's  tube.  The  color  of  this  filtrate  was  then  compared  with 
the  color  of  an  equal  bulk  of  the  original  liquid  contained  in  a  sim- 
ilar tube. 
These  results  were  as  follows: 
KAOLIN  TEST. 
Fruit  Colors. 
Effect  Produced, 
slightly  lighter 
Blackberry 
Cherry  (black) 
Cherry  (red) 
Cranberry 
Currant 
Elderberry 
Grape 
Huckleberry 
Plum 
Raspberry 
Strawberry 
decolorizes 
decolorizes 
no  change 
decolorizes 
slightly  lighter 
decolorizes 
slightly  lighter 
<  < 
KAOLIN  TEST. 
Other  Vegetable  Colors. 
Effect  Produced. 
Annatto 
Beet  Juice 
Brazilwood 
Cochineal 
Cudbear 
Fustic 
Litmus 
decolorizes 
no  change 
slightly  lighter 
no  change 
much  lighter 
much  lighter 
decolorizes 
