DETECTION  OF  STRYCHNINE  IN  CASES  OF  POISONING.  269 
microscope  is  very  characteristic.  The  color  of  the  latter  is  a 
beautiful  yellow.  The  formation  of  both  these  precipitates  is 
accelerated  by  rubbing  the  surface  of  the  tube  with  a  glass  rod. 
The  precipitate  formed  by  chromate  of  potash  gets  immediately 
a  dark  purple  color,  if  moistened  by  concentrated  sulphuric  acid. 
All  the  other  precipitates  get  the  same  color  if  they  are  dissolved 
in  a  small  quantity  of  strong  sulphuric  acid,  and  the  solution 
brought  into  contact  with  a  fragment  of  a  crystal  of  chromate  of 
potash  or  ferridcyanide  of  potassium. 
2nd.  The  possibility  of  detecting  strychnine,  if  mixed  or  com- 
bined with  animal  substances. 
In  all  the  following  experiments,  the  method  of  Professor  Stas 
was  used.  This  method,  by  which  all  organic  basic  poisons  can 
be  detected,  consists  in  treating  the  animal  substance,  which  is 
supposed  to  contain  a  poison,  with  spirit  of  wine,  acidulated  by 
pure  oxalic  or  tartaric  acid.  The  tincture,  after  having  been 
filtered,  is  evaporated  at  a  gentle  heat  on  a  water-bath,  and  the 
remaining  substance  dissolved  in  anhydrous  alcohol.  This  solu- 
tion is  filtered,  and  again  evaporated,  and  the  remaining  substance 
dissolved  in  water.  The  watery  solution,  after  having  been 
filtered  and  partly  evaporated,  is  saturated  with  bicarbonate  of 
soda,  and  afterwards  repeatedly  agitated  with  ether,  which  is 
made  alkaline  by  a  small  quantity  of  caustic  potash  or  soda.  If 
there  is  any  basic  organic  poison  present  in  the  animal  substance 
under  examination,  it  will  be  obtained  by  evaporating  the  ethe- 
real solution,  and  may  be  afterwards  tested  by  several  reagents 
to  find  out  its  nature. 
1st  Experiment — A  solution  of  J  of  a  grain  of  strychnine 
mixed  with  6  ounces  of  fresh  meat.  The  poisoned  meat,  treated 
as  mentioned,  afforded  small  crystals  of  strychnine,  of  which  the 
identity  was  proved  by  the  reagents  mentioned. 
2nd  Experiment. — The  white  and  yellow  of  one  egg  were 
mixed  with  J  of  a  grain  of  strychnine,  and  this  mixture  coagula- 
ted by  the  heat  of  boiling  water.  The  coagulum  being  treated 
according  to  Stas's  method,  almost  the  whole  quantity  of  the 
strychnine  was  recovered  in  white  crystals. 
Zrd  Experiment. — The  urine  of  24  hours  from  a  patient  in  the 
hospital,  to  whom  the  physician  administered  every  day  J  grain 
of  nitrate  of  strychnine,  was  divided  into  two  equal  parts,  and 
