January fih899m-}    Emetine  Octoiodide  and  Alkaloids.  19 
nine  sulphate  remains  in  solution.  The  flask  is  then  completely 
cooled,  and  water  enough  added  to  make  100  c.c.  Of  this  50  c.c, 
representing  again  1  gram  of  the  nux  vomica  but  deprived  of  the 
brucine,  are  then  filtered  off  and  run  out  from  the  burette  into  a  100 
c.c.  flask  containing  20  c.c.  decinormal  iodine  solution,  and  about  2 
c.c.  of  dilute  hydrochloric  acid.  The  amount  of  iodine  consumed 
by  the  strychnine  alone  is  then  determined  as  above.  Let  it  be  b. 
Then  b  x  43  9  (one  hundred  times  the  strychnine  factor)  gives  the 
percentage  of  strychnine  and  (a — b)  x  5 1  *79  is  the  percentage  of  bru- 
cine in  the  nux  vomica. 
To  test  the  exactness  of  this  method  we  prepared  a  solution  con- 
taining known  quantities  of  each  of  these  alkaloids  and  determined 
these  by  the  described  method.  The  results  as  can  be  seen  from 
the  following  table  are  fairly  satisfactory,  if  we  consider  the  well- 
known  difficulties  of  this  separation. 
The  solution  contained  0-16  per  cent,  strychnine  and  0  22  per 
cent,  brucine  (anhydrous). 
Iodine  consumed  by 
10  c.c.  before  the  re- 
moval of  brucine. 
Iodine  consumed  by 
10  c  c.  after  the  re- 
moval of  brucine. 
Found 
Strychnine  Brucine. 
Contained 
Strychnine.  Brucine. 
00843130 
0-0843  [32 
0-032397 
0-032397 
0-14 
0*14 
0-24 
0-24 
o-i6 
o'i6 
0  22 
022 
Following  is  a  report  of  drugs  which  we  have  so  far  assayed  both 
gravimetrically  and  iodometrically.  The  factors  are  those  given  for 
the  higher  periodides  in  our  previous  paper.13  For  nux  vomica  the 
mean  factor  was  taken,  which  is  equal  to  0-47845  parts  of  total 
alkaloids  for  I  part  iodine  consumed.  For  ipecac  root  the  factor 
0-5453  is  used,  which  is  based  upon  the  fact  that,  as  shown  at  the 
end  of  this  paper,  emetine  forms  a  hydriodide  heptaiodide  when 
treated  with  excess  of  iodo-potassium  iodide. 
Taking  Lefort  and  Wurz's  formula  for  emetine  we  get 
7-  X  126-53  :  482  98  ::i  :  factor  =  0-5453. 
The  factors  for  the  drugs  of  the  table  are  as  follows  : 
Mean  factor  of  strychnine  and  brucine  0*47845 
Atropine  0-2849 
Emetine  0-5453 
13 J.  Am.  Cheni.  Soc,  1898,  20,  724. 
