238  Cascarilla  Bark.  { ^m'May?if98arm' 
Fourteen  pounds  of  bark,  reduced  to  No,  40  powder,  were 
exhausted  by  percolation  with  chloroform  water  containing  3 
per  cent,  of  oxalic  acid.  The  percolate  was  made  faintly  alkaline 
by  ammonia  evaporated  at  a  low  temperature  to  one-fifth  of  its  vol- 
ume, allowed  to  become  cold,  and  filtered  from  the  crystallized 
magma  which  had  separated  out.  The  filtrate  was  precipitated  by 
an  excess  of  lead  acetate,  and  the  precipitate  collected  on  a  calico  fil- 
ter and  well  washed.  After  removal  of  the  excess  of  lead  by  the 
addition  of  sulphuric  acid,  the  clear  liquor  from  the  lead  sulphate 
was  rendered  faintly  alkaline  by  ammonia  and  agitated  with  three 
successive  portions  of  ether  to  withdraw  the  cascarillin  that  should 
be  present.  The  same  liquid  was  next  shaken  in  a  like  manner 
with  chloroform.  The  chloroformic  residue  will  be  referred  to  pres- 
ently. The  next  stage  in  the  series  of  operations  consisted  in  acidu- 
lating the  liquid  with  sulphuric  acid  (a  large  excess  of  acid  must  be 
avoided)  and  adding  to  it  Thresh's  reagent  in  quantity  sufficient  to 
effect  complete  precipitation.  The  precipitate,  after  being  washed 
on  a  filter  until  quite  free  from  free  iodine,  ammonium  or  potassium 
salts,  was  decomposed  by  freshly  precipitated  silver  carbonate  in 
the  presence  of  water  and  filtered.  The  filtrate  was  faintly  acidu- 
lated with  hydrochloric  acid  and  evaporated  over  a  water-bath  and 
again  filtered.  This  final  filtrate  was  precipitated  by  platinic  chlor- 
ide, and  the  precipitate  was  collected  and  thoroughly  drained. 
The  double  compound  of  base  and  platinum  salt  was  repeatedly 
crystallized  from  water  and  finally  washed  with  absolute  alcohol. 
The  purified  platinum  compound  crystallized  from  hot  water  in 
dark  yellow  hexagonal  plates,  and  from  weak  alcohol  in  octahedral 
form.  A  portion  of  the  product  was  dissolved  in  hot  water  and 
decomposed  by  sulphuretted  hydrogen  and  filtered.  The  filtrate 
was  evaporated  to  dryness,  and  the  residue  purified  by  re-solution 
in  a  sufficiency  of  warm  water  and  evaporation  until  a  white  minutely 
crystalline  chloride  of  the  base  was  obtained.  This  chloride,  when 
perfectly  dry,  was  practically  insoluble  in  alcohol,  and  when  heated 
it  melted  with  intumescence  and  gave  off  trimethylamine. 
Portions  of  platinum  compound  were  then  ignited,  with  the  fol- 
lowing results:  It  should  be  stated  that  they  represent  the  product 
of  three  different  extractions  of  the  bark.  Prior  to  ignition  they 
were  dried  at  105 0  C. 
