130 
The  Tests  for  Atropine. 
/Am.  Jour.  Pkarin. 
\      March,  1880. 
phenolphtalein  as  an  indicator.  One  molecule  of  either  soda  or  potash, 
as  required  for  replacing  one  molecule  of  quinine,  will  not  act  on 
phenolphtalein,  because  the  alkaloid  set  at  liberty  does  not  produce 
the  red  coloration.  But  the  least  excess  of  soda  or  potash  will  imme- 
diately be  indicated  by  the  red  color  due  to  the  action  which  now  sets 
in  between  soda  (or  potash)  and  phenolphtalein. 
In  my  first  investigation,  when  I  stated  that  the  alkaloids  were 
devoid  of  action  on  phenolphtalein,  I  had  not  tried  atropine,  but  now 
I  am  astonished  to  see  that  this  alkaloid,  quite  exceptionally,  is  able 
to  impart  a  red  coloration  to  phenolphtalein  paper,  thus  contradicting 
my  first  assertion  that  alkaloids  generally  were  deprived  of  such  an 
action.  This  new  experiment  of  mine  is  very  remarkable,  inasmuch 
as  it  is  in  perfect  accordance  with  Mr.  Gerrard's  test.  He  has  pointed 
out  that  atropine  (and  its  conveners)  is  more  powerfully  alkaline  than 
mercury,  whereas  other  alkaloids  are  unable  to  take  the  place  of  mer- 
cury in  the  mercuric  chloride.  With  regard  to  phenolphtalein  I  have 
likewise  demonstrated  that  atropine  is  the  only  alkaloid — speaking, 
however,  simply  of  the  more  generally  used  alkaloids — which  displays 
the  same  action  as  the  inorganic  alkalies.  Certainly,  this  is  a  very 
remarkable  coincidence,  speaking  much  in  favor  of  the  suggestion  that 
atropine  must  be  somewhat  particularly  constituted,  differing  from 
other  solid  alkaloids,  none  of  which,  as  far  as  we  actually  know,  shows 
the  same  behavior  towards  mercuric  chloride  or  phenolphtalein.  I 
have  also  tried  some  other  coloring  matters,  viz.,  cyanine,  methyl- 
orange,  phenacetolin,  tropaeolin,  and  found  them  to  be  acted  upon  by 
atropine  in  the  same  way  as  by  soda  or  potash.  Mercurous  chloride 
(calomel),  however,  is  not  blackened  by  atropine  as  it  is  by  soda, 
potash,  or  ammonia,  and  also  by  pyridine. 
It  remained  to  be  ascertained  that  the  above-mentioned  reactions  of 
atropine  were  not  due  to  traces  of  inorganic  alkalies,  a  slight  admix- 
ture for  instance  of  carbonate  of  sodium  or  potassium.  But  a  little  of 
the  atropine  under  examination  burnt  in  a  platinum  crucible  yielded 
no  residue  at  all,  nor  did  a  solution  of  phenolphtalein  assume  any 
coloration  when  I  afterwards  filled  the  crucible  with  it.  It  might 
therefore  be  granted,  that  my  specimen  of  atropine  was  fairly  pure. 
In  conclusion,  we  have  proved,  Mr.  Gerrard,  Dr.  Schweissinger, 
and  myself,  that  atropine  (and  hyoscyamine — Dr.  Schweissinger)  has 
an  alkaline  power  like  the  hydrates  of  sodium  or  potassium,  differing 
in  this  respect  from  (probably  all)  other  alkaloids. 
