AfebJruar'yPi*99m'}    Extraction  Ipecacuanha  Liquidum.  77 
we  calculate  the  above  titration  results  by  this  method  we  see  that 
there  is  a  difference  of  from  50  to  60  milligrammes  between  the 
results  of  volumetric  and  gravimetric  determinations,  e.g.: 
Gravimetric.  Volumetric.  Difference. 
•386  -337  -049 
•393  -342  -051 
•417  '359  '058 
•426  -367  -059 
This  difference  may  be  due  to  some  impurity,  but  more  probably 
to  the  third  alkaloid  which  is  present,  and  which  Paul  and  Cownley 
believe  to  have  a  much  higher  molecular  weight  than  either  eme- 
tine or  cephaeline. 
By  the  process  suggested,  fatty  matter,  resinous  bodies,  etc.,  are 
removed  by  agitation  with  ether-chloroform  in  acid  solution.  If 
this  part  of  the  process  be  carefully  conducted  it  becomes  unneces- 
sary to  subject  the  ether-chloroform  solution  of  alkaloids  to  the 
usual  purification  by  acid  treatment,  as  when  treated  by  the  latter 
method  the  ether-chloroform,  after  shaking  with  acidulated  water, 
has  been  proved  to  yield  no  residue  on  evaporation. 
The  drying  of  the  alkaloidal  residue  till  of  constant  weight  is 
tedious,  but  no  means  can  at  present  be  devised  for  shortening  this 
operation,  as  cephaeline  has  been  shown  by  Paul  and  Cownley  to 
lose  weight  at  ioo°  C,  and  hence  to  guard  against  this  loss  the 
residue  must  be  dried  below  8o°  C. 
The  advantages  claimed  for  the  suggested  assay  process  over  that 
official  are  the  two  very  important  ones  of  speed  and  accuracy.  The 
assay  can  be  easily  completed,  with  the  exception  of  drying  the 
residue,  well  within  the  time  required  by  the  official  process  for 
washing  the  lead  precipitate  alone.  A  residue  of  greater  weight  is 
extracted  which  has  been  proved  by  titration  to  be  equally  rich  in 
alkaloid.  From  the  mean  results  given  earlier  it  will  be  seen  that 
by  the  official  process  -389  gramme  is  extracted  and  -029  gramme  lost, 
that  is  to  say,  the  loss  is  between  and  ^  of  the  total  alkaloid 
present.  These  figures  are  based  on  the  results  obtained  on  carefully 
washing  the  precipitate  with  50  c.c.  water  which,  considering  the 
time  taken  (at  least  three  hours),  was  judged  a  fair  quantity;  but  if 
double  that  quantity  of  water  be  used  to  wash  the  precipitate,  it  has 
been  proved  to  still  contain  a  notable  proportion  of  alkaloid. 
The  foregoing  experiments  have  been  carried  out  in  the  phar- 
macy laboratory  of  the  Pharmaceutical  Society. 
