522 
Quinine  and  Homoquinine. 
Am.  Jour.  Pharm. 
Oct.,  1884. 
to  moist  air,  the  quinine  sulphate  rapidly  takes  up  4  per  cent,  of  water, 
but  the  homoquinine  almost  three  times  as  much,  namely,  11  to  12 
per  cent. 
It  was  of  especial  interest  to  acertain  the  behavior  of  homoquinine 
to  polarized  light,  since  the  alkaloid  on  account  of  this  behavior 
received  from  Whiffeu  the  name  "  ultraquinine."  According  to 
Whiffen  this  sulphate  in  acid  solution  showed  (a)0—  — 221°,  whilst 
quinine  sulphate  only  showed  (a)0=  —  196°.  Of  the  water  of  crys- 
tallization of  the  two  sulphates,  in  which  they  certainly  differ  from 
each  other,  Whiffen  makes  no  mention,  so  that  it  is  quite  possible  that 
the  difference  in  question  was  purely  dependent  upon  the  different 
quantities  of  water  of  crystallization  which  they  contain. 
In  my  experiments  the  amount  of  water  of  crystallization  was  first 
exactly  estimated,  and  then  a  quantity  of  each  of  the  hydrated  sul- 
phates corresponding  to  1*25  gram  of  anhydrous  salt  was  dissolved  in 
10  cc.  of  normal  hydrochloric  acid.  These  solutions  were  then  each 
diluted  with  water  up  to  25  cc,  and  finally  examined  at  £=50°  and 
7=220,  the  deviation  being  sometimes  determined  first  by  means  of 
the  quinine  solution,  and  then  this  solution  changed  for  the  homo- 
quinine solution,  and  sometimes  the  order  being  reversed.  In  this  way 
it  was  ascertained  that  the  two  solutions  did  not  differ  from  one  another 
in  respect  to  their  optical  behavior.  In  an  average  of  thirty  determina- 
tions a  =  25*92°,  which  gives  for  the  anhydrous  sulphate  (a)0=  — 
235-6°. 
Neutral  Tartrate  of  Homoquinine  is  obtained  by  mixing  a  hot  aqueous 
solution  of  the  sulphate  with  solution  of  Rochelle  salt.  It  forms  delicate 
white  concentrically  grouped  needles,  which  dissolve  with  some  diffi- 
culty in  hot  water  and  are  very  slightly  soluble  in  cold.  The  com- 
position of  the  salt  is  represented  by  the  formula — 
(C20H24N2O2)2,  C4H6Oe+2H20. 
0-3305  gram  of  air-dried  substance  gave  at  120°  C.  0-014  H20. 
Calculated  for  Found. 
H20   4-31      .  4-23 
The  tartrate  dried  at  120°C,  takes  up  from  moist  air  only  1  mole- 
cule of  H20  ;  it  has  then  the  same  percentage  composition  as  neutral 
tartrate  of  quinine. 
The  dissimilar  composition  of  the  two  tartrates  must  not  be  over- 
looked in  the  estimation  of  quinine  optically  by  the  method  of  Oude- 
