288     Fluorescent  Principle  of  Wild  Cherry  Bark  {Amj£Z™-Jg*im' 
was  evaporated  to  a  syrupy  residue  having  a  light  red  tint.  This 
residue  was  in  large  part  acidic  ammonium  acetate.  It  dissolved 
readily  and  completely  in  alcohol.  But  chloroform  and  ether  dissol- 
el  it  only  partially.  Their  solutions  gave,  on  spontaneous  evaporation, 
pasty  amorphous  residues  which  after  about  8  hours  become  wholly 
and  very  distinctly  crystalline.  On  diluting  the  original  acetic  resi- 
due with  water,  boiling  it  for  some  time  with  excess  of  dilute  sulphu- 
ric acid,  and  again  concentrating  it,  a  brown  red  pasty  sediment  formed. 
This  readily  dissolved  in  ammonia,  and  after  supersaturating  the  al- 
kali with  chlorhydric  acid  and  removing  all  the  ammonium  sulphate 
and  most  of  the  chloride  with  alcohol,  a  brown-red  residue  was  again 
obtained  from  the  alcoholic  solution  after  concentration.  Treatment 
of  this  with  ether  yielded  a  faintly  red  solution  which,  on  spontaneous 
evaporation,  gave  a  viscid  residuum,  becoming  wholly  and  decidedly 
crystalline  after  about  8  hours.  These  crystals  promptly  dissolved  in 
chloroform,  ether  and  alcohol,  and  were  also  soluble  in  water.  The  alco- 
holic and  aqueous  solutions  became  strongly  fluorescent  on  the  addition 
of  ammonia.  The  red  pasty  remainder  left  undissolved  by  the  ether  was 
easily  and  perfectly  soluble  in  ammonia  without  fluorescence. 
The  crystals  obtained  by  means  of  ether  in  this  instance  were  iden- 
tical in  properties  and  appearance  with  those  secured  by  the  same 
agency  from  the  acetic  residue  in  the  first  instance.  They  formed, 
in  slender  branched  filaments,  upwards  to  one  inch  in  length. 
Viewed  in  oblique  incident  light,  they  displayed  decided  rainbow  tints, 
which  may  result  from  prismatic  dispersion,  but,  were  probably,  the 
iridescence  of  diffraction.  Under  the  microscope  with  a  one-inch 
power,  these  crystals  showed  no  prismatic  form  although  their  appear- 
ance was  very  fine.  A  merely  incipient  polarescence  was  observable, 
which,  however,  develops  with  the  age  of  the  crystals  into  an  excel- 
lent appearance. 
The  proportional  quantity  of  this  crystalline  constituent  of  wild 
cherry  bark  is  exceedingly  small.  Without  the  fluorescing  property, 
as  a  guide,  it  would  have  been  practically  impossible  to  detect  and  iso- 
late it.  Judging  from  its  crystalline  form  it  does  not  appear  to  be 
mandelicacid,  a  decomposition  product  of  amygdalin.  It  may,  however, 
be  an  analogue,  or  a  substituted  derivative  of  it.  This  conjecture 
leads  to  the  legitimate  question,  whether  or  not,  it  is  amygdalin  as 
such,  from  which  the  benzoic  aldehyde  and  cyanhydric  acid  of  syrup 
of  wild  cherry  results. 
