'^"'•oct'yiS.^''^*}       Mayer's  Reagent  for  Alkaloids.  493 
late  a  table  for  the  correction  of  the  results  of  titration,  as  probably 
the  alkaloid  will  never  be  estimated  by  this  means. 
StryGhnine  and  brucine  in  mixture  with  the  two  alkaloids  in  mix- 
tures varying  from  60  per  cent,  to  35  per  cent,  of  strychnine,  and  in 
solutions  containing  1  part  in  200  of  the  mixed  alkaloid,  the  average 
equivalent  of  four  experiments  was  found  to  be  '0095.  For  rough 
comparisons  of  samples  of  nux  vomica  this  equivalent  might  be  used, 
but  ordinarily  it  is  best  to  estimate  the  alkaloids  by  their  weight. 
EMETINE. 
The  equivalents  of  this  alkaloid  in  different  degrees  of  dilution  w^ere 
presented  before  this  association  at  its  last  meeting.^  Detailed  com- 
ment is  unnecessary  here  as  it  was  given  last  year  by  myself,  and  has 
been  considered  thoroughly  by  others  in  different  places.  The  tables 
to  follow  were  the  same  as  those  which  I  have  already  given,  but  are 
now  offered  in  greater  detail. 
Observation  shows  that  with  the  presence  of  only  small  amounts  of 
free  acid  1  cc.  of  the  reagent  in  different  degrees  of  dilution  precipi- 
tates as  follows : 
1  in  200  ,   -0109 
1  in  300   -0105 
1  in  400   -0102 
1  in  500   -0100 
1  in  600   -0095 
The  precipitate  from  0*100  of  alkaloid  weighs  on  an  average  0*245 
grammes,  corresponding  to  40*81  per  cent,  alkaloid. 
Fluid  measures  30  cc.^  at  the  beginning  of  the  titration,  and  contains  3cc.  of 
1  per  cent,  by  vol.  sulphuric  acid. 
Cc.  Reagent  Required. 
Dilution. 
Equivalent. 
6-00 
1  in  500 
•0100 
6-60 
1  in  450 
•0101* 
7-35 
1  in  400 
•0102 
8-32 
1  in  350 
•0103* 
9-52 
1  in  300 
•0105 
11-21 
1  in  250 
•0107* 
13-76 
1  in  200 
•0109 
^  Proc.  M.  S.  P.  A.,  1887,  p.  93,  et  seq. ;  also  in  Pharm.  Era  i.  400.  et  seq. 
2  This  dilution  is  suited  to  2J  grammes  of  drug,  or  5  cc.  of  fluid  extract  (or 
about  }(  grammes  of  solid  extract). 
