638  Volumetric  Determination  of  Alkaloids.  {Am  Dec.?i§2arm' 
ether.  The  picroaconitine,  C^rl^NC^,1  is  probably  formed  from  I 
mol.  of  aconitine  by  the  absorption  of  1  mol.  of  water  and  elimina- 
tion of  1  mol.  of  benzoic  acid,  and  the  napelline,  C.2iH37NO10,  from 
1  mol.  of  picroaconitine,  by  the  absorption  of  1  mol.  of  water  and 
elimination  of  1  mol.  of  methyl  alcohol.  The  mother  liquors  from 
the  picroacontine  and  napelline  benzoates  contain  aconine,  C22H3g 
N09,  and  acetic  acid ;  this  points  to  the  formation  of  1  mol.  of  aco- 
nine from  I  mol.  of  napelline  by  the  absorption  of  1  mol.  of  water 
and  elimination  of  1  mol.  of  acetic  acid. 
When  aconine  is  distilled  with  barium  hydroxide,  paraffin  hydro- 
carbons, methylamine,  and  an  oily  compound  which  boils  at  about 
2450  and  has  an  odor  of  quinoline  are  obtained.  This  matter  is 
being  further  investigated. 
The  so-called  amorphous  aconitine  of  commerce  is  a  variable 
mixture  of  aconitine,  picroaconitine  and  napelline. 
ON  THE  VOLUMETRIC  DETERMINATION  OF  THE 
ALKALOIDS. 
By  L.  Barthe. 
I  have  ascertained  that  the  best  known  alkaloids  of  vegetable 
origin  are  without  action  upon  phenolphthalein,  which  they  leave 
in  the  state  in  which  it  comes  into  contact  with  them  ;  colorless  if 
the  medium  is  neutral  or  acid,  rose  colored  if  it  has  been 
rendered  alkaline  by  a  mineral  base.  Such  are  quinine, 
cinchonine,  cinchonamine,  cinchonidine,  quinidine,  morphine, 
codeine,  cocaine,  aconitine  (amorphous  or  crystalline),  strychnine, 
brucine,  veratrine,  pilocarpine,  duboisine,  sparteine.  On  combining 
this  observation  (made,  I  believe,  for  the  first  time)  with  the  well- 
known  property  of  the  vegetable  bases  to  turn  red  litmus  blue,  I 
have  founded  a  general  method  for  the  volumetric  analysis  of  the 
alkaloids. 
If  certain  vegetable  principles,  hitherto  regarded  as  alkaloids, 
do  not  react  appreciably  with  phenolphthalein  and  litmus,  it  is 
doubtless  because  their  properties  are  still  imperfectly  known,  and 
that  their  chemical  functions  require  accurate  determination.  For 
instance,  narcotine,  which  according  to  Pictet  and  Fluckiger,  can 
1Dunstan  and  Ince  (1891)  give  to  picroaconitine  the  formula  C31H45NO10  ; 
and  to  aconine  the  formula  C2 gH^NOi  1. 
