594  Contributions  to  Forensic  Chemistry.      { Am'^iSarm 
CONTRIBUTIONS  TO  FORENSIC  CHEMISTRY. 
By  Professor  G.  Dragendorff. 
The  author  reports  in  a  reprint  from  Pharmac.  Zeitschr.f.  Muss- 
land,  the  results  of  investigations  made  under  his  supervision 
with  a  number  of  drugs  more  or  less  employed.  Some  of  these  in- 
vestigations have  already  been  noticed  in  this  Journal,  namely,  on 
aloin,  by  Dr.  J.  Dietrich  (A.  J.  Ph.,  1 885,  p.  404) ;  on  convolvulin  and 
jalapin,  by  Dr.  J.  Miiller  (ibid.,  p.  556);  on  myoctonine,  by  Dr.  Sai- 
monowitz  (ibid.,  p.  459),  and  on  the  alkaloids  of  lobelia,  by  Dr.  H. 
von  Rosen  (ibid.,  1886,  p.  392).  The  remaining  researches,  which 
were  first  published  as  inaugural  dissertations  by  the  investigators, 
may  be  briefly  summarized  as  follows : 
Detection  of  Chloral. — Having  previously  shown  that  chloral 
hydrate  may  be  abstracted  from  aqueous  solutions  by  agitation  with 
ether  and  acetic  ether,  Dragendorff  recommends,  based  upon  the  re- 
searches of  Baron  Tiesenhausen,  the  treatment  of  urine  first  with 
petroleum-benzin,  then  with  ether,  when,  on  evaporation  of  the  latter 
solvent,  the  chloral  hydrate  is  left  behind.  Other  organic  mixtures, 
such  as  the  contents  of  the  stomach,  require  to  be  acidulated  with 
diluted  sulphuric  acid,  and  macerated  for  a  day  with  3  volumes  of 
strong  alcohol ;  the  filtrate  is  evaporated  spontaneously  until  the 
alcohol  has  been  volatilized,  when  the  aqueous  residue  will  yield  fat,. 
&c,  to  petroleum-benzin,  and  subsequently  chloral  hydrate  to  ether. 
Blood  and  organs  containing  much  blood  retain  the  chloral  within 
the  coagulum,  in  which  it  is  best  recognized  by  the  production  of 
chloroform  on  distilling  with  sodium  hydrate.  0*005  gm.  chloral 
hydrate  may,  by  these  processes,  be  readily  recognized  in  from  75  to 
100  ccm.  of  mixture. 
The  most  suitable  reactions  for  the  recognition  of  chloral  hydrate 
are  the  following : 
The  dry  chloral  hydrate  is  warmed  with  alcoholic  soda  solution  and 
a  little  pure  aniline;  the  odor  of  isonitril  is  still  distinct,  though 
faint,  with  1-60,000  gm.  of  chloral  hydrate. 
Heat  to  50°C.  the  hydrate  with  1  or  2  drops  of  concentrated 
aqueous  potassa  solution,  and  a  little  naphthol;  the  blue  color,  pro- 
duced also  with  chloroform,  is  recognized  with  1-24,000  gm.  of 
chloral  hydrate. 
Experiments  with  animals  show  that  chloral  hydrate  is  rapidly 
