*Sfc87h6!rm'}        'Iodo-Sulphate  of  Chinioidin.  129 
the  evaporation  of  the  alcohol.  This  amount  is  subtracted  from  the 
total  amount  of  liquid,  and,  for  the  remaining,  the  correction  is  calcu- 
lated with  reference  to  the  temperature  of  the  laboratory  during  the 
time  of  the  analysis.  The  dry  iodo-sulphate  of  quinia  is  taken  from  the 
filter  and  dried  on  a  water-bath,  in  one  of  a  couple  of  large  watch- 
glasses  closing  tightly  upon  each  other,  so  that  the  weight  of  the  sub- 
stance contained  in  the  glass  may  be  taken  without  the  access  of  the 
air.  When,  after  repeatedly  ascertaining  the  weight,  it  remains  con- 
stant, this  weight  is  noted  down,  and  to  it  is  added  the  product  of  the 
calculated  correction.  The  sum  of  this  addition  is  the  total  amount  of 
iodo-sulphate  of  quinia  obtained  from  the  mixed  alkaloids  subjected  to 
the  operation,  and  from  this  weight  the  amount  of  crystallizable  quinia 
can  be  calculated  by  the  use  of  Hauers's  formula,  2C40H24N2O4,  3(HO, 
S03),  3  I  (old  notation),  which  I  have  found  to  be  correct.  Accord- 
ing to  this  formula,  I  part  of  iodo-sulphate  of  quinia  dried  at  ioo°  C. 
represents  0*5509  part  of  anhydrous  quinia  or  07345  part  of  pure 
commercial  disulphate  of  quinia.1 
The  accuracy  of  this  determination*  may  be  proved  by  the  following 
examples  : 
0*294  gram  of  anhydrous  crystallized  quinia,  kindly  presented  to  me 
by  Dr.  O.  Hesse  in  October,  1873,  gave  °'54I  gram  of  herapathite 
dried  at  100°  C.  =0*298  gram  of  quinia. 
According  to  Hauers's  formula,  I  ought  to  have  obtained  0.5336 
gram  of  herapathite=o*294  gram  of  quinia. 
1*048  gram  of  bitartrate  of  quinia  gave  1.224  gram  of  herapathite= 
0,674  gram  of  quinia. 
According  to  the  formula  of  the  bitartrate  C^H^N^C^,  C4H6Os+ 
Aq=492  ;  1*048  of  bitartrate  represent  0*69  of  quinia,  so  that  I  ought 
to  have  obtained  1*255  gram  of  herapathite. 
1  Although,  as  Mr.  Umney  stated  at  the  Pharmaceutical  meeting  on  Wednes- 
day, November  3,  1875,  "manufacturers  only  believed  in  the  crystallizable  sulphate 
of  quinia  which  they  could  see  and  weigh,"  I  suppose  they  will  equally  be  satisfied 
by  seeing  and  weighing  the  quinia  herapathite  obtained  by  the  analyst  from  a  cer- 
tain amount  of  bark ;  for,  not  only  can  this  compound  be  easily  distinguished  from 
the  similar  compounds  of  the  other  Cinchona  alkaloids,  but  by  dissolving  it  in 
sulphurous  acid  and  precipitating  the  solution  by  caustic  soda,  quinia  is  obtained, 
which  may  be  easily  transformed  into  crystallized  sulphate. 
9 
