228  NOTE  ON  ATROPIA. 
Prof.  Ludwig  then  recommended  that  I  should  distil  a  small 
quantity  of  the  alkaloid  with  bichromate  of  potassa  and  sul- 
phuric acid,  in  order  to  obtain  in  this  manner,  if  possible, 
the  volatile  acid.  In  fact,  after  a  little  boiling,  the  sweetish 
odor  often  accompanying  benzoic  acid  became  perceptible, 
some  drops  of  oil  appeared  on  the  surface,  and  on  continu- 
ing the  boiling,  small  iridescent  scales  and  needles  made  their 
appearance  in  the  receiving  vessel,  which,  from  their  pungent 
odor  and  their  shape  as  observed  by  the  microscope,  were  easily 
recognised  as  crystals  of  benzoic  acid. 
This  distillation  was  subsequently  repeated  twice  with  larger 
quantities  (2  to  8  grammes)  of  atropia,  using  the  proportions  of 
5  parts  of  bichromate  of  potassa  and  15  of  oil  of  vitriol,  pre- 
viously diluted  with  3  times  its  weight  of  water,  to  every  two  of 
the  alkaloid.  Immediately  after  the  boiling  had  commenced, 
there  appeared  in  the  receiver  vapor  of  the  odor  of  oil  of  bitter 
almonds.  The  first  portions  of  the  distillate  gave  to  ether,  on 
being  shaken  with  it,  a  small  quantity  of  a  yellowish  oil,  which 
possessed  this  odor  besides  the  property  of  becoming  milky 
with  water  and  yielding  acicular  crystals  on  evaporation  with 
a  drop  of  fuming  nitric  acid.  When  the  boiling  had  continued 
for  10  minutes  a  considerable  quantity  of  benzoic  acid  had  col- 
lected on  the  surface  of  the  now  greenish  fluid  in  the  retort,  in 
the  form  of  a  white  froth,  which  was  at  once  obtained  pure  by 
filtering  and  washing.  Both  filtrate  and  washings  were  then 
distilled  nearly  to  dryness,  from  the  distillate  the  benzoic  acid 
extracted  by  agitation  with  ether,  then  combined  with  soda,  and 
from  the  concentrated  solution  of  the  soda  salt  again  separated 
by  means  of  hydrochloric  acid.  In  this  manner  about  one-fourth 
of  the  quantity  of  atropia  was  recovered  in  the  form  of  benzoic 
acid. 
Its  fusing  point  was  exactly  218°  F  ;  the  silver  salt  formed 
in  acicular  crystals  with  a  mother-of-pearl  lustre;  both  gave  in 
ultimate  analysis  the  numbers  required  for  benzoic  acid. 
The  residue  from  t  ie  distillation  contains  all  the  nitrogen  of 
the  atropia  in  form  of  ammonia ;  no  other  organic  bases  were  to 
be  found,  for  distillat  on^with  soda  lye  furnished  a  volatile  pro- 
duct which,  with  chloride  of  platinum,  gave  pure  double  chloride 
of  ammonium. 
