TEST  FOR  CERTAIN  ALKALOIDS. 
433 
limit  of  detection  being  — *  th ;  indeed,  75,000  is  quite  marked. 
a    100000  ' 
but  the  bichromate  scarcely  reaches  3000.  There  is  also  a  greater 
degree  intensity  as  well  as  persistency  of  color,  nor  is  there  any 
disposition  to  that  greenness  as  observed  in  the  reduction  of 
chromic  acid ;  and,  as  far  as  I  can  see,  it  is  entirely  free  from 
objection,  and  commends  itself  as  the  test  par  excellence.  It  is 
useful  as  a  precipitant  of  strychnia,  the  crystals  being  in  the 
form  of  very  long  spicule,  and  sometimes  needles,  which  strike 
a  splendid  color  with  sulphuric  acid. 
I  arrived  at  the  test  figures  thus  : — 1  grain  of  strychnia  was 
first  dissolved  in  100  of  water.  Of  this  solution,  1  drop  was 
added  to  999  of  water ;  a  fragment  of  nitro-prusside  was  then 
thrown  in,  and  agitated  till  dissolved.  Of  this  mixture,  1  drop 
was  let  fall  into  a  small  white-ware  dish,  and  dried  at  a  steam  heat, 
and  on  cooling  the  color  was  developed  by  drawing  across  the 
spot  a  glass  rod  dipped  in  sulphuric  acid. — Ghem.  News,  London, 
June,  21,  1862. 
ON  THE  NITRO-PRUSSIDE  OF  SODIUM  AS  A  TEST  FOR  CERTAIN 
ALKALOIDS. 
By  John  Horslet. 
Since  announcing  the  above  test  I  find  by  using  it  in  the 
manner  stated,  that  the  plea  for  the  non-detection  of  strychnia 
in  the  presence  of  morphia  no  longer  holds  good,  as  subsequent 
experiments  with  five  and  even  ten  times  the  amount  of  morphia 
prove. 
I  find  also  that  one  drop  of  a  solution  of  strychnia  of  one  per 
cent,  strength,  agitated  with  one  or  two  drops  of  a  saturated  so- 
lution of  the  nitro-prusside,  produces  an  abundant  crop  of  crys- 
tals for  an  infinitude  of  experiments  with  sulphuric  acid, — the 
crystals  under  the  microscope  being  in  long  nitre-shaped  tufts 
and  needles.  A  similar  experiment  with  brucia  produces  larger 
and  broader  needles  having  lancet  points,  totally  different  from 
strychnia,  besides  being  different  in  its  reaction  with  sulphuric 
acid. 
A  similar  experiment  with  morphia  also  shows  certain  charac- 
teristics ;  thus,  the  crystals  are  for  the  most  part  of  a  peculiar 
28 
