244  Cinchonidine  in  Quinine  Sulphate.  {Am^r,'mSxm' 
obtained  in  endeavoring  to  determine  the  amount  of  cinchonidine  in 
commercial  quinine  sulphate  by  a  certain  optical  method  which  is  not 
accepted  as  giving  accurate  results. 
The  samples  are  referred  to  by  numbers,  and  the  following  are  the 
results  obtained: — 
Table  A. 
No. 
TV  titer  of  crystalliza- 
tion.    Per  cent. 
Quinine  sul- 
phate. 
Per  cent. 

Lincnoni- 
dine  sul- 
phate. 
Per  cent. 
1 
15-14 
84-86 
none 
2 
15-70 
84-30 
none 
3 
15  90 
84-10 
none 
4 
14-11 
85-89 
none 
5 
15-17 
84-83 
trace 
6 
13-49 
86-51 
none 
7 
11-70 
88-30 
none 
8 
fnot  determined;"] 

0-39 
9 
-J  ealt  fully  crystal-  J- 

0-61 
10 
I  ized.  J 

4-60 
11 
13-86 
84-64 
1-50 
12 
16-12 
83-88 
none 
13 
14-70 
82-90 
2-40 
14 
12-00 
88-00 
trace 
15 
13-90 
84-90 
1-20 
16 
13-98 
84-82 
1-20 
17 
12-40 
84-20 
3-40 
18 
13-00 
82-40 
4-60 
19 
15-10 
81-50 
3-40 
20 
13-32 
85-81 
0-87 
21 
14-90 
80-88 
4-22 
22 
14-20 
84-81 
0-99 
23 
15-25 
81-59 
3-16 
24 
13-67 
81-43 
4-90 
25 
8-10 
87-35 
4-55 
26 
10-37 
84-19 
5-44 
27 
15-40 
79  50 
5-10 
28 
12-64 
82-86 
4-50 
These  results,  therefore,  do  not  bear  out  the  statement  that  all  the 
sulphate  of  quinine  of  commerce  contains  more  than  5  per  cent,  of 
cinchonidine  sulphate,  for  out  of  nearly  thirty  samples  examined  at 
different  times,  the  average  proportion  of  cinchonidine  found  only 
amounted  to  2.04  per  cent. 
The  circumstance  that  some  samples  of  quinine  sulphate  of  inferior 
quality  contain  an  undue  proportion  of  cinchonidine  is  now  well 
known,  and  this  fact  was  first  pointed  out  by  Dr.  Paul  some  years  ago 
(Phar.  Jour.  [3],  vii,  p.  672),  when  illustrating  the  defective  char- 
