ON  ATROPIA. 
233 
it  is  isomeric  with  cinnamic  acid.  The  lime-salt,  which  is  readily 
obtained  in  fine  crystals,  appears  to  be  0*8  H7  Ca  O4+3  Aq. 
Tropia.  I  have  as  yet  been  unable  to  prepare  this  alkaloid  in 
a  perfectly  pure  form.  On  evaporating  the  original  solution  of 
its  hydrochlorate,  the  salt  crystallizes  out  in  needles,  which  are 
again  readily  dissolved  by  water.  Oxide  of  silver  added  to  the 
solution  renders  it  strongly  alkaline,  though  no  silver  remains  in 
solution.  On  evaporating  the  filtrate  a  crystalline  residue  is  left 
behind,  which  appears  to  have  absorbed  carbonic  acid  from  the  air, 
and  to  have  been  also  otherwise  changed ;  at  least  the  platinum- 
salt  could  not  again  be  obtained  from  it. 
From  the  solution  of  the  hydrochlorate  of  tropia  chloride  of 
platinum  precipitates  this  double-salt  in  fine  orange-colored  crys- 
tals, which  give  a  yellowish  red  powder.  Its  composition  is 
Cie  NH17  04,  HC1,  PtCl2.  With  chloride  of  gold  there  is  likewise 
obtained  a  double  salt  in  well-developed  crystals.  The  alkaloid 
appears  to  undergo  some  decomposition  when  kept  heated  at  356 
— 380°  F.  with  baryta  water  for  17  hours,  still  the  decomposition 
is  not  complete,  nor  is  its  product  volatile.  But  by  continued 
boiling  of  the  aqueous  solution  of  the  alkaloid  small  portions  of 
it  are  volatilized ;  for  this  reason  the  distillate  obtained  from 
tropia  with  baryta  water  possesses  a  slightly  alkaline  reaction, 
and  in  the  residue  are  found  traces  of  atropiate  of  baryta. 
Atropiate  of  tropia  is  uncrystallizable,  at  ordinary  temperature 
of  a  viscid  consistency,  and  fuses  readily  with  heat.  A  solution 
containing  2  J  per  cent,  produced  no  enlargment  of  the  pupil.  Its 
composition  is  represented  by  d6  NHX7  04,  Cis  Hg  04  +  3  Aq. 
Two  equivalents  of  the  water  only  are  driven  off  at  184°  F. 
Atropia  is  decomposed  likewise  by  hydrochloric  acid.  Heated 
with  fuming  acid  for  four  hours  in  the  water-bath,  the  solution 
still  retained  some  atropia,  but  after  continuing  the  action  for  two 
hours  more  at  221°  F.  it  yielded,  with  chloride  of.  platinum, 
crystals  resembling  those  of  the  tropia-salt.  Here  there  was 
likewise  formed  an  acid  which  had  separated  in  the  form  of  oily 
globules ;  these,  however,  I  have  as  yet  been  unable  to  identify 
with  atropic  acid. 
In  connection  with  the  above  I  have  instituted  a  series  of  ex- 
