362 
Detection  of  Blood. 
f  Am.  Jour.  Pharm. 
I     August,  1899. 
The  importance  of  a  trustworthy  means  of  identifying  blood  or 
blood  constituents  like  hemoglobin,  methemoglobin  and  hematin 
in  numerous  judicial  cases  and  the  value  of  a  combination,  on  many 
rather  difficult  occasions,  of  the  spectroscopic  test  and  of  the 
methods  of  preparing  the  characteristic  crystals  of  hemin  (as 
described  by  leichmann,  Hoppe-Seyler,  Brilcke  and  Preyer),  with  the 
"  ozone-transferring  "  action  of  the  coloring  matter  of  blood  towards 
guaiacum,  has  induced  me,  for  many  years,  to  pay  special  attention 
to  the  last-named  blood-test  and  to  look  for  improvements  of  the 
hitherto  known  methods,  which  in  some  respects  were  far  from 
being  thoroughly  satisfactory.  As  it  happens  in  many  cases,  some 
accidental  observations  have  led  to  the  right  way  nearly  as  well 
as  systematic  experiments. 
Many  years  ago  (in  1866),  after  having  attended  the  lectures  of 
C.  F.  ScKbnbein  (the  chemist  of  Bale,  well  known  in  England  by  his 
acquaintance  with  Faraday  and  other  celebrated  naturalists)  and 
seen  his  experiments  concerning  the  action  of  blood-cells  on  hydric 
peroxide  and  solution  of  guaiacum  resin,  I  had  gathered  a  series  of 
experiences,  which  formed  the  chief  content  of  a  lecture  held  at 
Zurich  (in  1875),  but  never  published  in  print.  The  method  then 
demonstrated  having  proved  useful  in  a  practice  of  almost  thirty 
years,  I  could  not  hesitate  to  mention  it  in  the  above-named  paper, 
"  On  the  Use  of  Guaiacum  Resin  as  a  Reagent."  The  details  of 
this  method  can  be  noted  very  briefly  in  this  place,  the  more  so 
as  they  may  be  found  in  the  above-mentioned  essay,  and  as  the 
method  has  been  communicated  and  discussed  by  R.  Otto,  in  the 
supplementary  part  of  his  "  Anleitung  zur  Ermittlung  von  Giften," 
etc.,  VII,  Ed.  (1897). 
While  the  authors  above  referred  to  mainly  recommended  to  mix 
the  blood  solutions — (obtained  by  extraction  of  a  fresh  or  old 
blood-stain  with  small  quantities  of  water,  either  alkaline  or  acidu- 
lated with  acetic  acid) — under  suitable  conditions  first  with  an  alco- 
holic guaiacum  solution  and  then  with  transferable  oxygen  in  the 
form  of  hydric  peroxide  or  of  the  analogous  compound  contained  in 
old  and  isolated  turpentine  oil  (for  instance,  the  liquid  of  Hiinefeld, 
v.  i.),  and  to  observe  the  formation  of  the  so-called  "  guaiacum 
blue,"  the  method  which  I  have  proposed  aims  at  the  preparation 
of  an  intimate  and  durable  mixture  of  the  coloring  matter  of  blood 
derived  from  the  blood  stain  with  guaiacum  resin.    This  mixture 
