32  Adulteration  of  Tartaric  Acid.  \A™'£TimT' 
made,  and  enclosed  in  a  stoppered  bottle,  and  kept  under  water  in 
the  dark.  This  preparation  is  less  liable  to  change  than  pure  oxygen- 
ated water.  The  object  stained  with  blood,  if  it  be  white,  is  put  into 
a  little  cup,  then  moistened  with  water  to  dissolve  out  the  blood-stain, 
and  washed  in  distilled  water  ;  this  water  is  then  submitted  to  the  ac- 
tion of  these  reagents.  If  the  thing  stained  be  colored,  and  the  stain 
little  or  not  at  all  visible,  it  must  be  moistened  and  then  pressed  be- 
tween two  or  three  sheets  of  white  blotting  paper,  and  tried  first  with 
the  guiaicum.  If  the  stain  be  of  blood,  a  reddish  or  brown  spot  will 
form  on  the  paper.  One  of  the  sheets  should  be  treated  with  ammo- 
nia, and  the  stain  will  become  crimson  or  green.  A  second  sheet, 
treated  with  tincture  of  guiaicum  and  ozonised  ether,  will  give  a  blue 
color  more  or  less  intense,  according  to  the  quantity  of  the  blood. 
To  recapitulate:  1.  If  the  stains  or  scales  of  blood  appear  recent, 
the  corpuscles  may,  after  the  necessary  precautions,  be  examined  un- 
der the  microscope,  and  their  presence,  diameter,  &c,  observed,  which 
will  enable  one  to  diagnose  the  origin  of  the  blood,  whether  human  or 
animal.  2.  If  the  stains  be  old  and  the  blood  changed,  the  reaction 
with  the  tincture  of  guiaicum  would  make  the  presence  of  blood  prob- 
able ;  but  its  actual  presence  cannot  be  affirmed  without  spectrum  ex- 
amination, or  the  production  of  crystals  of  hydrochlorate  of  haematin  ; 
one  of  the  two  is  sufficient.  It  is  unnecessary  to  add  that  these  re- 
actions do  not  show  whether  the  blood  is  human  or  animal. — Qhem. 
News,  Dec.  5,  1873. 
ADULTERATION  OF  TARTARTIC  ACID. 
By  H.  Maclagan. 
In  the  account  of  the  proceedings  of  the  Am.  Pharm.  Association, 
in  the  November  number  of  the  Journal,  I  noticed  a  reference  to  the 
presence  of  sulphuric  acid  in  commercial  tartartic  acid.  That  it  is 
sometimes  present,  and  in  considerable  quantity,  I  can  fully  attest, 
having  once  suffered  considerable  annoyance  therefrom.  Complaint 
was  made  by  a  customer  of  our  seidlitz  powders — that  there  was 
something  wrong  with  them,  as  a  quantity  of  white  powder  remained 
in  the  tumbler  after  drinking.  I"  found,  on  mixing  one,  that  such  was 
indeed  the  case — that  when  the  effervescence  was  about  ended,  the 
mixture  became  cloudy,  and  in  a  very  short  time  a  considerable  white 
deposit  had  accumulated  in  the  bottom  of  the  glass.  This  was  col- 
lected and  examined,  and  proved  to  be  bitartrate  of  potassa.  Sus- 
