216     ON  THE  ACTIVE  PRINCIPLES  OF  THE  STRYCHNACEiE. 
sation,  as  well  as  in  solubility  ;  the  same  chemist  had  before  no- 
ticed similar  variations  in  the  composition  of  strychnia.  It  is 
readily  perceived,  from  the  properties  ascribed  to  strychnia  es- 
pecially, and  brucia,  by  Pelletier  and  Caventou,  Pettenkofer, 
Geiger  and  Merck,  that  these  chemists  operated  with  mixtures 
of  the  alkaloids.  For  this  reason  statements  as  to  the  quantity 
of  the  respective  alkaloids  to  be  found  in  either  nux  vomica  or 
ignatia  seed,  made  previous  to  Wittstock,  are  not  to  be  relied  on. 
The  latter  observer  states  that  10  ounces  of  nux  vomica  yield  12J 
grains  of  strychnia  and  31J  of  brucia,  while  according  to  Giese- 
ler,  10  ounces  of  ignatia  seed  yield  72  grains  of  strychnia. 
Pelletier  and  Henry  obtained  between  40  and  50  grains  of  this 
impure  strychnia  from  10  ounces  of  nux  vomica. 
These  discrepancies  find  their  explanation  in  the  peculiar 
character  of  that  portion  of  the  alkaloids  which  is  not  readily 
precipitated  by  alkalies. 
The  alkaloid  which  received  the  name  of  strychnia  is  recorded 
as  scarcely  soluble  in  water  and  alkalies.  Planta,  whose  obser- 
vations will  in  most  cases  be  found  at  least  as  trustworthy  as 
those  of  others  who  are  much  more  frequently  quoted,  never  uses 
the  expression  "  insoluble/'  in  such  cases,  but  says  not  percepti- 
bly soluble,  and  this,  as  a  matter  of  course,  is  the  case  with  all 
alkaloids,  since  none  of  them  are  ever  completely  insoluble  in 
water  or  completely  precipitated  by  alkalies  proper.  Brucia  was 
called  originally  the  precipitate  which  falls  down  from  mother  li- 
quors of  crystallisations  of  strychnia  by  the  addition  of  more 
soluble  alkali,  and  igasuria  that  which  finally  deposited  from 
the  alkaline  solution  on  standing.  With  the  exception  of  Planta, 
who  mentions  the  difficulty  with  which  brucia  is  precipitated  by 
ammonia,  I  find  on  record  but  one  instance  in  which  the  circum- 
stance is  mentioned  which  enables  me,  without  entering  more 
closely  into  a  consideration  of  the  subject,  to  give  a  rapid  as  well 
as  accurate  method  for  determining  strychnia  in  the  presence  of 
the  other  alkaloids  ;  it  is  this,  in  a  paper  published  by  that  ex- 
cellent chemist,  Dr.  F.  L.  Winckler,  of  Darmstadt,  in  1835,  Re- 
pertorium  f.  de  Pharmacie.  Bd.  li.  p.  369,  wherein  he  mentions 
the  solubility  of  brucia  in  ammonia  and  caustic  alkalies  and 
