200  Artificially  Colored  Red  Wine.  {AmApXfre7*rm" 
DETECTION  OF  AKTIFICIALLY  COLOEED  RED  WINE 
(CLARET). 
By  J.  Herz. 
To  30—50  cc.  of  the  wine,  or  if  the  quantity  of  coloring  matter 
in  the  wine  is  small,  100  cc.  concentrated  to  30  cc,  20 — 30  cc.  of  a 
saturated  solution  of  magnesium  sulphate,  and  10 — 20  cc.  of  soda 
solution  are  added,  stirring  well;  if  necessary  the  treatment  is  repeated 
until  the  liquid  is  colorless,  or  nearly  so.  The  nitrate  is  made  acid 
with  dilute  sulphuric  acid  (1  :  3),  and  if  sulphonic  acid  colors  are 
present  the  red  color  reappears.  The  most  commonly  used  member 
of  this  group,  acid-magenta  (rosanilinesulphonic  acid),  yields  a  violet- 
red  solution,  and  can  be  estimated  by  comparing  the  tint  with  magenta 
solutions  of  known  strength.  One  mgram.  of  magenta  per  litre  can 
be  distinctly  detected  in  30  cc.  of  wine  without  previous  concentra- 
tion. When  archil  (orseille)  colors  are  present,  the  filtrate  is  bluish, 
and  when  made  acid  turns  a  litmus-red  color.  To  test  for  magenta 
under  such  circumstances,  Blarez'  method  of  shaking  with  lead  dioxide 
is  used;  this  destroys  the  orseille  and  natural  color,  Cazeneuve's 
method  is  not  recommended.  To  test  for  other  colors  in  the  mag- 
nesium hydroxide  precipitate,  the  gelatinous  mass  is  stirred  up  with 
hot  water,  allowed  to  settle,  and  the  liquid  decanted  off.  If  only  the 
natural  color  of  the  wine  is  present,  or  bilberry  has  been  used,  this 
liquid  is  yellow-brown ;  if  archil  has  been  used,  dark-violet ;  if 
ponceau,  onion  or  ponceau  red  ;  if  cassissine,  pale-red  or  dark-yellow ; 
if  vinicoline  bordelaise,  a  yellow-red  to  yellow-brown  liquid,  which 
when  poured  on  sulphuric  acid  gives  a  violet  ring.  By  shaking  the 
colored  liquid  with  amyl  alcohol,  ponceau  yields  an  onion-red  residue ; 
vinicoline,  a  dark-brown  one ;  cassissine,  a  dirty-green,  violet  at  the 
edge,  turned  yellow  by  strong  hydrochloric  acid.  The  precipitate  is 
a  dark-grey  or  brownish-grey  color  when  the  natural  or  vegetable 
colors  only  are  present ;  with  archil,  it  is  violet ;  with  magenta  (acid 
or  ordinary),  dirty  white ;  with  cassissine,  dirty  yellow-brown ;  with 
vinicoline,  crimson-red.  The  precipitate  is  mixed  with  sand,  dried, 
and  extracted  with  ether ;  the  extract  contains  any  ordinary  magenta 
which  can  be  identified  in  the  usual  manner  by  dyeing  wool,  or  cassis- 
sine which  dyes  wool  red-brown  and  leaves  a  yellow-brown  residue 
in  the  dish.  The  dyed  wool  becomes  yellow  when  treated  with 
strong  hydrochloric  acid  and  colorless  with  ammonia.  When  wine  is 
shaken  with  amyl  alcohol,  and  the  colored  extract  evaporated,  the 
