432 
NEW  REAGENT  FOR  STRYCHNIA. 
doubtless  prove  a  valuable  reagent  in  chemical  laboratories,  is 
now  prepared  on  a  large  scale  by  Messrs.  Evans  and  M'Bryde, 
Union  Alkali  Works,  St.  Helens,  Lancashire. — Chem.  News, 
London,  June  28th,  1862, 
ON  THE  APPARENT  DIFFICULTY  OF  DETECTING  STRYCHNIA  IN 
THE  PRESENCE  OF  MORPHIA— DISCOVERY  OF  A  MORE 
POWERFUL  REAGENT  FOR  STRYCHNIA. 
By  John  Horsley,  F.  C.  S.,  Analyst  for  the  County  of  Gloucester. 
The  first  part  of  the  title  of  this  paper  has  reference  to  that 
of  Dr.  Reese,  contained  in  the  "  Chemical  News"  for  June  7. 
It  is  very  true,  as  stated  by  Dr.  Reese,  that  morphia  in  excess 
has  the  power  of  preventing  the  effect  of  chemicals  upon  strych- 
nia, as  ordinarily  practised ;  J?ut  the  difficulty  of  detecting  it  is 
more  apparent  than  real,  all  that  is  necessary  being  (if  the  two 
alkaloids  have  really  been  extracted  from  a  dead  body)  to  adopt 
the  method  of  precipitation  of  strychnia  by  the  addition  to  the 
concentrated  aqueous  or  neutral  solution  of  a  few  grains  of 
neutral  chromate  of  potash,  as  suggested  by  me  at  the  British 
Association  for  1856,  aiding  the  formation  of  the  golden-colored 
crystalline  precipitate  by  brisk  agitation  for  a  minute  or  so  with 
a  glass  rod,  then  carefully  decanting  the  supernatant  liquor 
containing  the  morphia  (the  chromate  of  which  is  longer  form- 
ing ;)  or  it  may  be  passed  through  a  very  small  filter,  and  the 
chromic  salt  of  strychnia  collected  for  experiment  with  strong  sul- 
phuric acid,  the  merest  particle  of  the  salt  being  sufficient.  Under 
the  microscope,  the  crystals  of  chromate  of  strychnia  are  in  the 
form  of  little  golden-colored  stars  ;  but  the  corresponding  salt  of 
morphia  is  that  of  little  round  granules,  with  a  dark  ring  on  the 
outside.  As  a  matter  of  course,  these  latter,  when  touched  with 
sulphuric  acid,  turn  green,  and  so,  when  in  excess,  have  the 
effect  of  masking  the  reaction  of  strychnia,  which  remains  passive. 
As  regards  the  new  reagent, — that  is,  the  nitro-prusside  of 
sodium, — which  I  used  quite  by  chance  the  other  day,  and  was 
astonished  at  the  result,  a  comparison  between  it  and  the  bi- 
chromate of  potash  is  immensely  in  favor  (where  no  other  alka- 
loid but  strychnia  is  present)  of  the  nitroprusside,  the  extreme 
