THE  AMERICAN 
JOURNAL  OF  PHARMACY. 
JULY,  1885, 
ON  ARBUTIN,  THE  BITTER  PRINCIPLE  OF  THE  COW- 
BERRY (VACCINIUM  VITIS-IDiEA,  Lm.). 
By  Edo  Claassen. 
In  this  Journal  (July  number,  1870),  I  announced  the  existence  of 
a  bitter  principle,  vacciniin,  in  the  leaves  (resp.  the  whole  plant)  of 
the  cowberry,  and  described  its  preparation  from  the  same. 
At  the  same  time  I  also  published  several  properties  of  it,  but  could 
not  then  give  the  matter  a  thorough  investigation.  It  was  not  until 
now  that  I  had  leisure  to  continue  the  examination,  and  to  state  that 
the  bitter  principle  found  in  that  plant  is  not  a  peculiar  one,  but  iden- 
tical with  another  already  known,  viz.,  with  arbutin,  the  bitter  princi- 
ple occurring  in  several  other  ericaceous  plants,  particularly  in  Arbu- 
tus Uva  Ursi,  Lin.  In  order  to  come  to  the  above  conclusion,  a  series 
of  tests  were  made  with  the  above  vacciniin,  and  these  were  compared 
with  tests  made  with  arbutin  prepared  for  this  purpose  from  the  leaves 
of  Arbutus  Uva  Ursi,  Lin. 
Before  describing  these  tests  I  may  be  allowed  to  say  that  there  was 
no  difference  perceptible  either  in  the  form  and  shape  of  the  crystals 
of  both  these  bitter  substances  under  the  microscope  (they  form  four 
and  six  sided  prisms,  with  a  doma,  i.  e.,  two  planes,  sharpening  their 
ends),  nor  in  their  solubility  in  water,  alcohol  and  ether,  and  also  not 
in  their  bitter  taste. 
The  tests  made  were  the  following : 
1.  Heated  on  platinum  foil,  both  melt  to  a  clear  liquid  (which  by 
and  by  turns  black),  and  are  entirely  consumed  by  increased  heat. 
2.  Heated  in  a  glass  tube,  both  melt  at  first,  then  turn  black,  and 
give  off  fumes  of  a  peculiar  smell  and  of  acid  reaction. 
3.  Concentrated  sulphuric  acid,  and  also  hydrochloric  acid,  dissolve 
both  without  color. 
4.  Concentrated  nitric  acid  colors  both  orange,  then  dissolves  them 
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