6 
ASSAY  OF  ALKALOIDS. 
obliges  me  to  alter  my  intention,  and  to  reply  beforehand  to  an  , 
attack  which  is  alike  unsound  and  unfair. 
The  paper  of  Mr.  Groves,  it  seems,  was  called  out  by  a  self- 
constituted  query  of  his,  "  On  the  Assay  of  Alkaloids  in 
Pharmaceutical  Extracts."  In  it  the  author  proposes  to  give  a 
general  review  of  the  different  processes  that  have  at  various  times 
been  proposed  for  the  purpose,  and  to  sum  up  his  experience  as  to 
which  is  the  best  for  general  adoption.  His  researches  have  ex- 
tended to  as  many  as  three  modes  of  conducting  an  assay,  and 
to  two  abortive  propositions.  The  three  first  named  are  all 
founded  on  the  precipitation  of  alkaloids  by  iodohydrargyrate  of 
potassium,  for  which  I  published  before  all  others  a  systematic 
procedure  in  the  volume  of  Transactions  of  the  American 
Pharmaceutical  Association  for  1862.  Instead  of  a  proposal 
to  substitute  something  better  for  this  method  of  mine,  Mr. 
Groves  converts  by  far  the  greater  part  of  his  pages  into  an 
effort  to  bring  my  statements  into  discredit,  and  so  far  carried 
away  the  judgment  of  his  hearers  at  Bath  as  to  receive  per- 
mission to  print  this  paper. 
First  in  order,  there  is  a  general  assertion  on  the  part  of 
Mr.  Groves  that  the  iodohydrargyrates  of  the  alkaloids  obtained 
by  the  reagent,  which  I  directed  in  1862,  ought  to  have  the 
formula  :  Alkaloid  +  HI  +  2HgI,  that  is,  an  equivalent  of  the 
hydriodate  of  the  alkaloid  with  two  equivalents  of  iodide  of 
mercury.  In  consequence,  those  of  my  assays  in  which  I  em- 
ploy respectively  1  or  3  or  4  or  6  equivalents  of  mercury  for 
precipitation  are  incorrect.  Besides,  I  am  charged  with  having 
established  as  a  general  formula  that  of :  Alkaloid  +  HI  -f  one 
HgL 
As  I  shall  investigate  Mr.  G.'s  formulas  at  another  point,  I 
will  here  only  dispose  of  this  matter  so  far  as  my  own  are  con- 
cerned. The  fact  is  that,  with  the  exception  of  the  one  for 
opium,  I  have  published  detailed  assays  only  for  atropia,  strych- 
nia, and  brucia,  and  in  each  of  these  my  results  are  exactly 
those  required  by  Groves'  formula,  viz.  :  Alkaloid  +  HI  +2HgI. 
The  two  last  quoted  assays  were  read  before  the  Baltimore 
Meeting  of  the  American  Pharmaceutical  Association  in  1863, 
(Proceed.  1863,  p.  251),  dated  a  whole  year  before  my  critic's 
paper,  and  of  the  same  month  in  which  my  assay  of  opium 
