RECOGNITION  OF  BLOOD-SPOTS  UPON  LINEN. 
527 
celain  capsule,  when  its  ignition  by  means  of  a  burning  match 
may  be  attempted.  If  this  does  not  succeed,  the  capsule  may  be 
heated  by  a  spirit-lamp,  when  the  alcohol  contained  in  the  water 
is  the  first  to  evaporate,  and  may  be  ignited  by  a  burning  match. 
A  portion  of  the  distillate  may  be  set  aside ;  and  if  a  consider- 
able quantity  still  remains,  the  following  experiment  may  be  made 
with  it.  The  neck  of  a  small  glass  funnel  is  loosely  closed  by 
means  of  a  small  glass  rod ;  some  platinum-black  is  then  put  into 
the  funnel,  moistened  with  a  few  drops  of  distilled  water,  and 
the  alcoholic  fluid  is  then  allowed  to  flow  upon  it  in  a  very  slow 
stream  by  means  of  a  cotton  thread,  which  may  act  as  a  siphon. 
A  fluid,  with  an  acid  reaction,  then  drops  from  the  funnel ;  this 
is  carefully  neutralized  by  a  few  drops  of  very  dilute  solution  of 
potash,  and  evaporated  to  perfect  dryness  on  the  water-bath.  A 
portion  of  the  residue  may  be  added  to  some  very  dilute  chloride 
of  iron,  to  obtain  the  ordinary  reaction  of  the  acetates  ;  another 
portion  may  be  triturated  with  a  small  quantity  of  arsenious  acid, 
and  heated  in  a  small  test-tube,  when  the  characteristic  strong 
odor  of  oxide  of  kakodyle  is  produced.  These  two  latter  tests, 
however,  require  rather  larger  quantities  of  acetic  acid  before 
they  will  succeed  ;  as  a  general  rule,  the  test  with  the  platinum- 
black,  to  which  the  reaction  with  chromic  acid  and  the  test  of 
combustibility  may  be  added,  is  quite  sufficient. 
The  platinum-black  employed  for  this  purpose  is  precipitated 
from  a  very  dilute  solution  of  chloride  of  platinum  by  means  of 
zinc ;  it  is  washed  first  with  muriatic  acid,  then  with  nitric  acid, 
and  lastly  with  potash.  The  author  concludes  with  a  series  of 
experiments,  which  sufficiently  prove  the  applicability  of  the 
method  Chemical  Gazette,  August,  1854,  from  Strauch's 
Inaugural  Dissertation,  Dorpat,  1852. 
ON  THE  RECOGNITION  OF  BLOOD-SPOTS   UPON  LINEN  AND 
COTTON  STUFFS. 
By  C.  Wiehr. 
In  the  course  of  last  year  the  author  had  to  examine  some 
pieces  of  stuffs  which  bore  red  spots ;  these  were  a  dirty  old  piece 
of  coarse  unbleached  linen  and  a  blue  and  white  checked  pillow- 
cover.  The  object  was  to  ascertain  whether  the  red  spots  upon 
them  were  produced  by  blood. 
With  this  object,  a  red  fragment  was  cut  out  of  each  piece  of 
