Am^-]9p05.arm-}    Contributions  from  H.  M.  Got  din.  215 
grammes)  was  made  alkaline  with  ammonia  and  shaken  out  four 
times  with  a  mixture  of  four  parts  ether  and  one  chloroform,  using 
200  c.c.  of  this  mixture  each  time.  The  ether-chloroform  was  dis- 
tilled off  completely,  the  residue  taken  up  with  about  10  c.c.  of 
acidulated  (1  per  cent.)  water,  and  the  liquid  filtered  into  a  small  sep- 
arator, washing  the  vessel  from  which  the  ethereal  liquid  was  distilled 
and  the  filter  repeatedly  with  small  quantities  of  acidulated  water. 
The  alkaloid  was  now  shaken  out  with  heavy  ether-chloroform  (1  ether, 
2  chloroform)  and  ammonia,  and  the  ether-chloroform  completely 
distilled  off.  The  residue  was  taken  up  with  a  little  chloroform 
N 
and  20  c.c.       sulphuric  acid,  and  after  the  removal  of  the  chloro- 
40 
form  by  a  current  of  air,  the  assay  was  finished  alkalimetrically, 
using  Mayer's  reagent  as  precipitant.  The  dregs  in  the  percolator 
were  tested  for  alkaloid  as  usual,  but  none  was  found. 
Using  this  as  a  standard,  I  assayed  the  drug  by  many  different 
methods,  but  no  method  gave  as  good  results  as  those  obtained  by 
the  standard  method.  Those  obtained  by  method  B,  after  reduc- 
ing the  drug  to  a  No.  100  powder,  came  nearest  to  those  obtained 
by  the  standard. 
~  Acid  Consumed        percentage  of 
Method  Used.  by  2*5  Grammes.  Alkaloid. 
Standard   .  11*5  c.c.  2*92 
A    ..................  9'6  c.c.  2  43 
B    .   io*2  c.c.  2*59 
It  will  be  noticed  that  000635  was  taken  as  the  factor  of  emetine 
N 
for  each  cubic  centimetre  of  —  acid.     This  is  based  upon  the  as- 
40 
sumption  that  the  formula  of  emetine  is  C30H40N2O5  (Kunz  Krause, 
Arch.  d.  Pharm.,  225,  461  :  232,  466)  and  that  the  salts  of  emetine 
correspond  to  the  formula  CggH^NoCh  2A  where  A  is  one  molecule 
of  a  monobasic  acid.  As  this  formula  is  not  yet  accepted  all  around,1 
the  above  factor  will  possibly  have  to  be  slightly  changed.  But  as 
in  the  present  case  determinations  were  only  made  with  a  view  of 
comparing  the  results  obtained  by  the  standard  method  with  those 
obtained  by  the  simpler  methods,  it  is  immaterial  what  factor  we 
use  provided  it  be  the  same  in  all  cases.    The  only  fact  that  re- 
1Lefort  and  Wurz,  An.  Chitn.  Phys.  (5),  12,  247  ;  Glenard,  ibid.,  8,  233  ;  Paul 
and  Cownley,  Pharm.  J.  (3),  24,  6r. 
