10  Substitute  for  Ethyl  Alcohol.        { A n^Hy%T- 
for  these  preparations.  They  are  simply  extracts  and  fluid  extracts 
made  with  a  new  menstruum,  and  when  they  are  recognized  by  the 
U.S  P.,  the  present  officinal  names  will  doubtless  remain  unchanged, 
as  it  is  only  the  menstruum  that  is  changed,  the  quality  and  strength 
being  undisturbed.  For  the  present  it  is  considered  sufficient  to 
place  conspicuously  on  the  label,  under  the  U.S.P.  title  the  words 
"  Made  with  acetic  acid,"  especially  as  the  new  menstruum  involves 
no  increase  of  risk  of  serious  mistakes. 
It  is  proposed  that  the  next  paper  shall  investigate  the  very  im- 
portant and  very  difficult  exhaustion  of  cinchona. 
THE  ASSAY  PROCESS. 
Early  in  this  investigation  it  became  necessary  to  have  a  con- 
venient and  fairly  accurate  process  of  assay  for  the  mixed  alkaloids. 
The.  short  and  easy  methods  of  Messrs.  Dunstan  and  Short,  given 
in  the  British  Pharm.  Journ.  and  Trans,,  3d  Series,  Vol.  XIII,  pp. 
665-1055,  and  Vol.  XIV,  p.  621,  and  given  in  the  British  Pharma- 
copoeia, were  found  objectionable  on  some  accounts,  but  chiefly 
because'  the  results  are  too  high.  For  example,  a  table  is  given 
at  p.  1055,  wherein  from  seven  samples  the  percentage  of  total  alka- 
loids ranged  from  3  04  to  3  90  per  cent.,  with  an  average  of  3  29  per 
cent.  This,  in  the  writer's  experience,  is  much  too  high,  and  there 
is  a  probability  that  the  plus  error  may  be  due  to  weighing  the 
chloroform  extract  as  alkaloids.  The  most  recent  authority  noticed 
is  the  new,  1898,  British  Pharmacopoeia,  but  its  method  is  liable  to 
the  same  -objection  of  weighing  a  chloroform  extract  as  alkaloid. 
The  U.S.P.  of  1890  has  an  excellent  method  that  avoids  this  source 
of  error  by  titrating  the  alkaloids.  This  method — U.S.P.,  1890, 
pp.  152,  et  seq. — first  makes  a  dry  extract  and  then  assays  that  for 
use  in  its'standardized  preparations. 
Two  grammes  of  the  dry  extract  is  dissolved  by  shaking  in  a 
separator\vith  20  c.c.  of  a  previously-made  mixture  of  2  volumes 
of  alcohol  (91  per  cent.),  1  volume  of  water  of  ammonia  (10  per 
cent.),  and  1  volume  of  water.  Then  20  c.c.  of  chloroform  (99  per 
cent.) 'is  added,  and  the  mixture  is  agitated  during  five  minutes. 
The  chloroform  is  then  allowed  to  separate  and  is  drawn  of!  as  far 
as  possible  by  the  stopcock.  This  washing  out  is  repeated  with 
two  farther  portions  of  chloroform  of  15  c.c.  each.  The  chloroform 
solutions  are  then  collected  in  a  beaker  and  exposed  on  a  water- 
