232 
ON  ATROPIA. 
the  remarks  of  the  discoverers  of  cocaina  on  its  relation  to  atropia, 
and  the  note  of  Ludwig  and  Pfeiffer  on  the  decomposition  by 
means  of  chromic  acid  ;  all  of  which  pointed  very  strongly  to  the 
probability  of  one  of  the  products  of  the  decomposition  belonging 
to  the  group  of  aromatic  compounds. 
The  experiments  which  I  now  communicate  are  not  yet  conclu- 
ded, but  are  given  in  their  present  shape,  since  I  have  ascertained 
that  the  same  subject  was  under  examination  by  others. 
When  atropia,  in  a  sealed  tube  with  a  hot  saturated  solution  of 
baryta  in  water,  is  kept  in  the  water-bath  for  two  or  three  hours, 
a  clear  colorless  solution  is  formed,  which,  when  afterwards  dilu- 
ted with  water  and  submitted  to  distillation,  yields  but  traces  of 
a  volatile  base,  and  from  the  residue  carbonic  acid  precipitates 
carbonate  of  baryta  free  from  organic  matter.  The  filtrate  from 
this  precipitate,  which  is  neutral  and  contains  slight  traces  of 
baryta,  on  evaporation  leaves  a  colorless  amorphous  varnish  in 
which,  after  standing  for  some  weeks  over  oil  of  vitriol,  there 
appear  a  few  stellate  crystals,  less  soluble  in  water  than  the  re- 
mainder, and  containing  all  the  baryta  still  present.  The  soluble 
part  of  the  extract,  forming  the  principle  portion,  is  an  uncrys- 
tallizable  salt  formed  by  the  splitting  of  atropia  after  receiving 
two  equivalents  of  water.  Dissolved  in  water  it  is  at  once  rend- 
ered milky  on  the  addition  of  hydrochloric  acid ;  after  a  few 
seconds  acicular  crystals  of  an  acid  are  deposited  while  a  base 
remains  in  solution  combined  with  hydrochloric  acid. 
To  obtain  the  acid  the  mixture  is  filtered,  and  the  filtrate  re- 
peatedly shaken  with  ether,  which  dissolves  the  acid.  I  shall 
name  it  atropic  acid,  and  the  base  tropia.  The  reaction  by  which 
they  form  is  represented  by  the  following  formula : 
(C3iN  H23  06)+2  HO=  C18  H8  04+C16  H17  N04 
Atropia.  Atropic  acid.  Tropia. 
The  crystals  obtained  from  a  solution  in  alcohol  are  oblique 
prismatic  plates  ;  formed  from  watery  solutions  they  are  acicular 
and  possess  the  odor  of  benzoic  acid,  and  melt  and  form  an  oil  at 
222°  F.  The  saturated  solution  in  hot  water  congeals  to  a 
crystalline  mass  on  cooling.  The  acid  contains  72*97  per  cent. 
C  and  5*41  per  cent.  H,  therefore  its  formula  is  Cis  Hs  Oi,  and 
