Am.  Jour,  Pharm. 
Aug.,  1880, 
Determination  of  ^inia. 
397 
2 1 2°F.,  represents  0*55055  parts  of  pure  anhydrous  quinia,  or  0*734. 
parts  of  pure  disulphate  of  quinia. 
Although  I  feel  convinced  that  this  process  of  estimating  the 
amonnt  ofquinia  in  a  mixture  of  cinchona  alkaloids  is  not  one  which, 
even  in  the  hands  of  inexperienced  persons^  will  give  accurate  results 
in  a  short  time^  I  have  some  hope  that  in  the  hands  of  experienced 
analysts  it  may  prove  a  satisfactory  one,  if,  before  applying  it,  they 
study,  as  I  have  done,  the  action  of  the  reagent  upon  solutions 
of  1  gram  of  quinia,  quinidia,  cinchonia  and  cinchonidia,  each  of  them 
separately  in  40  grams  of  the  above-mentioned  acidulated  alcohol.  If 
they  do  so  they  will  find  that  the  iodosulphates  of  quinia  and  of 
quinidia  thus  obtained  have  an  analogous  composition,  and  are  identical 
with  the  compounds  described  by  Herapath,^  whilst  the  iodosulphates  of 
cinchonia  and  cinchonidia  have  a  different  composition  from  the  former, 
and  both  require  more  iodine  to  be  transformed  into  the  optical  iodo- 
sulphates described  by  Herapath.  In  the  meantime  they  will  find  that 
of  all  these  iodosulphates,  that  of  quinia  is  the  most  insoluble  in  alco- 
hol, and  is  therefore  precipitated  the  first  of  all  and  alone  by  a  judicious 
addition  of  the  reagent.  Therefore  the  purity  of  the  obtained  iodo- 
sulphate  of  quinia  can  be  easily  tested  by  dissolving  it  in  boiling  alcohol 
and  letting  it  crystallize  by  cooling.  If  the  quinia-herapathite  be  really 
pure  the  mother-liquor  will  only  be  slightly  lemon-colored,  and  if 
evaporated  on  water-bath  100  parts  of  the  mother-liquor  at  61  °F.  will 
leave  not  more  than  0*125  parts  of  residue. 
That  the  reagent  can  also  be  applied  to  test  the  commercial  value  of 
the  various  sulphates  of  quinia  of  commerce  will  be  easily  understood 
by  carefully  studying  the  process. 
Soon  after  the  first  publication  of  my  process  in  the  "  Pharmaceutical 
Journal'*  Prof.  Jorgensen  of  Copenhagen  published  in  "Journal  fur 
Praktische  Chemie"  a  classical  paper,  "  Ueber  den  sogenannten  Hero- 
pathit  und  iihnliche  Acid  Perjodide,"  in  which  he  describes  not  less 
than  7  crystallized  compounds  of  quinia  with  iodine  and  sulphuric  acid. 
The  reading  of  this  very  elaborate  paper  not  only  explained  to  me  the 
causes  of  the  different  results  obtained  by  me  by  the  addition  of  a 
solution  of  iodine  to  an  acid  solution  of  sulphate  of  quinia  in  alcohol, 
but  induced  me  also  to  send  a  sample  of  my  reagent  to  Prof.  Jorgensen 
with  the  request  to  try  it  and  to  investigate  the  composition  of  the 
^  **  Proceedings  cf  the  Royal  Society,"  vol.  ix,  p.  10. 
