Am.  Jour.  Pharm.j 
March,  1886.  J 
The  Tests  for  Atropine. 
129 
THE  TESTS  FOR  ATROPINE. 
By  Professor  Fluckiger. 
We  are  indebted  to  Mr.  A.  W.  Gerrard  for  an  interesting  paper  on 
"A  New  Reaction  and  Test  for  Atropine  and  the  Mydriatic  Alka- 
loids/' published  in  the  Pharmaceutical  Journal,  vol.  xiv  (1884),  pp. 
718  and  729.  It  was  shown  by  the  author  that  the  mydriatic  alka- 
loids are  possessed  of  a  quite  exceptional  alkaline  power  towards 
mercuric  chloride,  from  the  aqueous  solution  of  which  they  precipitate 
mercuric  oxide,  the  other  natural  alkaloids  giving  no  precipitate  at  all 
with  mercuric  chloride,  or,  at  least,  in  no  case  separating  mercuric 
oxide.  Mr.  Gerrard's  statements  were  confirmed  by  Dr.  Schweis- 
singer,1  of  Heidelberg,  who  moreover  ascertained  that  hyoscyamine 
shows  the  same  behavior,  but  not  homatropine.  As  to  my  own  ex- 
perience, I  likewise  found  Mr.  Gerrard's  results  to  be  correct.  One 
milligramme  of  atropine  dissolved  in  1  c  cm.  alcohol  (0*830  specific 
gravity)  yields  a  yellowish  precipitate  as  soon  as  1  c.cm.  of  a  deci- 
normal  solution  of  mercuric  chloride  (27*1  gm.  in  1  litre  of  water)  is 
added.  On  standing  for  an  hour  or  two  the  precipitate  (an  oxy chloride 
of  mercury)  turns  red,  and  proves  to  consist  finally  of  mercuric  oxide. 
The  same  precipitate  fails  to  make  its  appearance  if  other  alkaloids 
are  used.  Thus,  for  instance,  a  saturated  aqueous  solution  of  codeine 
may  be  boiled  with  mercuric  chloride  without  affording  a  precipitate 
of  mercuric  oxide;  on  cooling  a  white  or  whitish  compound  of  the 
alkaloid  and  the  chloride  crystallizes  in  the  liquid. 
In  a  paper  contained  in  the  Archiv  der  Pharmacie,  vol.  ccxxii 
(1884),  605,  I  examined  the  action  of  phenolphtalein  on  alkaline  sub- 
stances, and  stated  that  alkaloids  are  unable  to  produce  the  same  red 
coloration  with  solutions  of  phenolphtalein  as  the  inorganic  alkalies. 
In  repeating  now  these  experiments  I  may  even  add  that  the  same 
fact  applies  to  so  eminently  an  alkaline  substance  as  pyridine.  Litmus 
paper  turns  intensely  blue  if  moistened  with  pyridine,  but  paper  im- 
bued with  a  solution  of  phenolphtalein  (0*318  in  50  c  cm.  alcohol  and 
50  c  cm.  water)  is  not  reddened  by  pyridine. 
E.  Leger2  made  a  curious  application  of  this  behavior  of  alkaloids. 
He  titrates  sulphate  of  quinine  by  means  of  soda  or  potash,  using 
1  Pharmaceutische  Zeitung,  1884,  No.  79,  Supplement,  October  1;  also  in  the 
Archiv  der  Pharmacie,  ccxxii  (1884),  827.    See  also  Amer.  Jour.  Phar.  (1884),  p,  206, 
2  Journal  de  Pharmacie  et  de  Chimie,  xi  (1885),  425. 
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