Am.  Jour<  Phann. 
Aug.,  1888. 
Characters  of  Antipyrin. 
417 
Erdmann^s  Reagent  (sulphuric  acid  with  a  trace  of  nitric  acid). — 
Greenish-yellow  coloration  in  the  acid  liquid.  If  a  slight  excess  of 
acid  be  added  without  mixing  an  orange  zone  is  formed  at  the  surface 
of  seperation. 
DeVrij  and  Sonnenschein^ s  Reagent  (sodium  phosphomolybdate). — 
White  precipitate  in  the  acid  solution. 
Dragendorff^s  Reagent. — In  acid  solution  green  precipitate,  then 
orange  red  ;  liquid  colorless. 
BouchardaVs  Reagent. — Brick  red  precipitate,  the  reaction  being 
perceptible  in  an  acidified  solution  of  one  in  20,000  of  antipyrin.  In 
an  alkaline  liquor  a  precipitate  is  no  longer  produced  when  diluted  to 
one  in  600. 
Picric  Acid  (saturated  solution). — Yellow  precipitate,  at  first  amor- 
phous, but  afterwards  becoming  crystalline.  This  reaction  is  percep- 
tible in  a  solution  of  1  in  4000.  It  can  be  carried  out  in  the 
following  manner  :  Place  upon  an  object  glass  one  drop  of  a  solution 
of  antipyrin  ;  then  add  a  drop  of  picric  acid  solution.  When  the 
crystals  have  formed  they  can  be  seen  under  the  micsoscope  as  yellow 
rectangular  tables,  or  sometimes  acicular,  associated  in  a  network  or 
arborescent  tufts.  The  two  bodies  react  in  a  similar  manner  in  alcohol 
solution,  but  the  crystals  are  then  larger. 
Nessler's  Reagent. — -In  acid  solution,  an  abundant  red-yellow  pre- 
cipitate. 
Tannin. — Abundant  white  precipitate. 
Gold  Chloride. — Yellow  precipitate. 
Platinum  Chloride. — Yellow  precipitate. 
OTHER  REAGENTS. 
Perchloride  of  Iron. — One  drop  of  the  reagent  and  1  cc.  of  one 
per  cent,  solution  give  a  blood-red  coloration.  This  reaction  is  very 
distinctly  manifest  in  a  solution  of  1  in  2000,  and  is  still  very 
perceptible  in  1  in  50,000.  The  liquid  reddened  by  perchloride  of 
iron  examined  in  the  spectroscope  in  a  layer  one  centimetre  thick  with 
diffused  sunlight  shows  an  absorption  band  extending  from  the  orange 
to  the  violet. 
Saturated  Solution  of  Mercurous  Nitrate. — One  cc.  of  reagent  and 
2  cc.  of  one  per  cent,  solution  give  a  yellow  precipitate  floating  above 
a  blood-red  liquid. 
