Am.  Jour  Pharir . 
Sept.,  1880 
The  Purity  of  Spues, 
461 
in  pale  yellow  leafy  crystals,  have  been  obtained,  and  are  described  in 
detail. 
§uinhydrone, — As  is  well  known,  this  substance  dissolves  very  easily 
in  warm  water,  but  it  is  partly  decomposed  thereby  into  quinone  and 
hydroquinone,  the  solution  acquiring  the  characteristic  smell  of  quinone. 
It  dissolves  in  hot  glacial  acetic  acid  apparently  unaltered,  and  crystallizes 
out  on  cooling  in  greenish-black  plates  or  prisms.  It  is  insoluble  in  hot 
or  cold  petroleum  ether  and  in  ligroin.  It  is  soluble  with  extreme  diffi- 
culty in  boiling  chloroform,  crystallizing  out  on  cooling  in  small  plates^ 
but  by  this  treatment  the  greater  part  of  the  quinhydrone  is  decomposed 
into  quinone,  which  is  carried  away  with  the  chloroform  vapor,  and  into 
hydroquinone,  which  separates  in  colorless  crystals.  When  heated  it 
evolves  bluish-violet  fumes  and  gives  a  bluish-black  sublimate. 
The  author  does  not  agree  with  the  structural  formula  assigned  by 
Graebe  or  Wichelhaus  to  this  body,  but  is  of  opinion  that  quinhydrone 
is  to  be  regarded  as  a  compound  of  one  molecule  of  hydroquinone  with 
one  molecule  of  quinone,  as  by  the  action  of  acetic  anhydride  on  it  at 
160  to  170°  diacetylhydroquinone  and  quinone  were  obtained,  the  for- 
mer approximating  to  the  theoretical  quantity.  Phenoquinone,  C^gH^g 
O4,  and  methylquinhydrone,  C2,>H2oOg,  or  CgH402.2CgH4  (OHOCH3), 
have  been  examined  and  the  above  formulae  assigned  them  by  the  author, 
who  disputes  the  accuracy  of  the  formulae  C^gH^^jO^,  and  C2oHjgOg,  as 
given  them  by  Wichelhaus. 
The  Percentage  of  EXTRACTIVE  SUBSTANCES  soluble  in 
ALCOHOL  as  a  CRITERION  of  the  PURITY  of  SPICES.^ 
By  Max  Biechele. 
The  author  employs  the  following  method:  A  flask  of  about  120  cc. 
contents  is  fitted  with  a  cork,  through  one  of  the  two  holes  in  which 
passes  the  stem  of  a  funnel  of  about  7  cm.  diameter;  through  the 
other,  a  tube  leading  to  the  top  of  an  upright  Liebig*s  condenser.  Five 
grams  of  the  spice  to  be  tested,  previously  dried  at  ^o^C,  are  placed 
on  a  filter,  which  should  not  quite  fill  the  funnel,  covered  with  a  disk 
of  filter  paper,  and  absolute  alcohol  poured  through  until  the  flask  is 
half  full.  The  funnel  is  then  covered  with  an  inverted  funnel,  the 
stem  of  which  has  been  broken  off,  leaving  an  aperture,  through  which 
' '*  Corr.-blatt  d.  Vereins  analytisehsr  Chsnniker,"  z,  70.  Reprinted  from  the 
"Journ.  of  the  Amer.  Chem.  Soc."  ' 
