ON  THE  TOXICOLOGY  OF  STRYCHNIA. 
357 
and  agitated  in  a  bottle  or  long  tube,  with  about  half  an  ounce 
of  chloroform ;  after  subsidence,  the  chloroform  is  drawn  off  by 
means  of  a  pipette,  transferred  to  an  evaporating  basin,  and  the 
chloroform  expelled  over  a  water-bath  ;  the  residue  must  then  be 
moistened  with  concentrated  sulphuric  acid,  and  exposed  for 
some  hours  to  the  temperature  of  a  water-bath,  by  which  proceed- 
ing, all  organic  matter  except  the  strychnine  is  destroyed.  The 
charred  mass  is  then  treated  with  water,  and  the  solution  filtered 
'to  separate  the  carbon  ;  excess  of  ammonia  is  now  added,  and 
the  solution  again  agitated  with  about  one  drachm  of  chloroform  ; 
if  on  evaporating  a  small  portion  of  this  chloroform  solution,  and 
treating  the  residue  with  concentrated  sulphuric  acid,  any  char- 
ring takes  place,  the  preceding  process  must  be  repeated,  when 
the  last  chloroform  solution  will  afford  the  strychnine  sufficiently 
pure  for  conclusive  testing.  For  this  purpose  a  small  quantity 
is  taken  up  in  a  capillary  tube,  and  allowed  to  evaporate  on  the 
smallest  spot  possible  of  a  warm  porcelain  capsule,  by  adding 
successive  drops  until  the  whole  is  evaporated  on  the  spot.  If 
the  quantity  is  large — say  from  ^  of  a  grain  to  a  larger  quantity 
—the  method  we  have  pursued  is  similar  to  that  employed  by  Dr. 
De  Vry  and  others,  viz.,  moistening  the  spot  (when  the  capsule 
is  quite  cold)  with  concentrated  sulphuric  acid,  and  then  adding 
a  minute  fragment  of  bichromate  of  potash.  If,  however,  the 
quantity  is  very  small,  no  color  will  be  perceived  by  this  mode 
of  testing,  then  the  sulphuric  acid  rendered  slightly  yellow  by 
chromic  acid  will  be  found  successful. 
We  would  here  remark  that  the  recommendation  to  stir  the 
spot  moistened  with  sulphuric  acid  with  a  glass  rod,  previous  to 
the  addition  of  the  bichromate,  is  highly  objectionable,  and  will 
frequently  occasion  failure,  by  removing  the  acid  sulphate  of 
strychnine,  which  would  otherwise,  by  adhering  to  the  porcelain, 
facilitate  the  action  of  the  test.  The  superiority  of  our  mode  of 
operating  will  be  seen  by  the  following  analyses,  performed 
during  the  last  few  days.  On  the  26th  ult.,  at  three  o'clock 
p.m.,  l-30th  of  a  grain  of  strychnine  was  given  to  a  rabbit  weigh- 
ing nearly  four  pounds ;  at  four  a  second  l-30th  ;  at  half-past 
four  a  third  dose  was  administered,  after  which  he  evinced 
slight  signs  of  twitching  on  being  touched,  or  on  a  noise  ;  at 
five  a  fourth  dose  was  given ;  at  half-past  five  a  glass  beaker  fell 
