Am.  Jour.  Pliarm. "i 
March,  1887.  J 
Kernels  Quinine  lest. 
145 
the  result  which  would  be  obtained  with  a  mixture  of  90*83  quinine 
sulphate  with  9'17  of  cinchonidine  sulphate.*  In  this  manner,  qui- 
nine sulphate  containing  an  admixture  of  10*5  per  cent,  quinidine  sul- 
phate would  produce  a  deviation  of  5*17,  that  is  to  say  a  deviation 
precisely  equal  to  that  produced  by  pure  cinchonidine  sulphate. f 
I  have  here  supposed  that  an  alcoholic  solution  is  operated  upon, 
because  the  memoir  of  M.  Uudemans  furnishes  directly  the  data  neces- 
sary for  the  calculation  of  this  particular  case ;  but  in  principle  there 
is  no  difference  when  the  salt  is  dissolved  in  water  by  the  aid  of  sul- 
phuric acid.  The  delicacy  is,  however,  a  little  greater,  and  the  error 
a  little  less  in  the  latter  case,  the  relations  between  the  specific  rotatory 
powers  of  the  three  acid  salts  being  a  little  less  unfavorable  than  those 
obtaining  between  the  neutral  salts.  Now,  for  example,  when  a  devia- 
tion of  -12-13,  is  observed  for  pure  quinine  sulphate,  the  presence  of 
two  per  cent,  quinidine  sulphate  in  the  quinine  salt  would  suffice  to 
reduce  the  deviation  to  -11*60,  while  to  produce  the  same  result  it 
would  be  necessary  that  the  quantity  of  cinchonidine  sulphate  mixed 
with  the  quinine  salt  should  amount  to  11*8  per  cent. 
Thus  then  with  the  alcoholic  solution  quinine  sulphate  containing 
only  ten  hundredths  of  impurity  might  be  mistaken  for  pure  cinchon- 
idine sulphate,  and  with  the  acidulated  aqueous  solution  the  possible 
error  would  vary  from  one  to  six  times  as  much.  This  consideration 
of  the  case  will  make  it  unnecessary  to  refer  to  other  sources  of  error. 
Before  concluding  I  will  add  another  remark. 
It  is  by  design  that  I  have  made  use  of  the  term  tolerance  in  treat- 
ing of  this  subject.  If  it  could  be  maintained  that  the  presence  of  a  few 
hundredths  of  the  alkaloids  allied  to  quinine  would  be  incapable  of 
causing  any  real  prejudice  to  patients,  if  certain  manufacturers  pretend 
that  the  elimination  of  these  last  traces  of  impurity  presents  difficulties 
for  them,  if  various  reasons  induce  us  to  allow  for  the  present  a  certain 
latitude  to  the  manufacturer,  it  is  nevertheless  incontestable  that  there 
is  here  only  a  question  of  tolerance  to  be  dealt  with ;  the  pure  quinine 
sulphate  is  the  official  article,  the  normal  article,  the  imperfectly  puri- 
fied salt  being  nothing  more  than  a  make-shift,  j    The  conversion  of 
*  6.7Q1=(6*436-.r)2X157-4  ,  arX2XH8*7 
20  20        whence  the  weight  of  cinchonidine 
salt  .r=0-04  or  9*17  per  cent,  of  the  mixture. 
f  (100-:i')157*4+2ir5fel  18-57X100  ;  whence  ff=10*5. 
X  "The  official  quinine  sulphate  should  not  contain  any  of  the  other  cin- 
chona alkaloids."— Codex,  1884,  p.  299. 
10 
