THE  LEAVES   OF  ARCTOSTAPHYLOS  UVA-URSI, 
69 
decolorized,  it  is  obtained  in  the  form  of  brown  crystals,  one 
inch  in  length  and  half  an  inch  in  thickness.  According  to  its 
composition  it  may  be  considered  as  the  product  of  oxidation  of  a 
substance,  the  composition  of  which  is  equal  to  that  of  camphor. 
IVHj^f  O,  H,=  C»  H10Or. 
2equiv.  of  camphor. 
A  wateiy  solution  of  the  crystals,  mixed  with  a  solution  of  chlo- 
ride of  iron,  asumes  an  indigo-blue  color  ;  after  a  few  seconds 
this  changes  to  green,  and  then  to  brownish-yellow.  This  reac- 
tion indicates  a  connection  with  the  salicyle  group  and  the  arctu- 
rin  might  perhaps  be  concidered  as  a  sal  icy  1  ite  of  the  oxide  of 
ethyle,  combined  with  the  elements  of  oxalic  acid. 
Cso  H„  07=C2  03  +  C4  H5  0+C14  H5  03. 
It  is  well  known  that  Gaultheria  procumbens  (fam.  of  Ericinese) 
contains  salicylate  of  the  oxide  of  methyle  in  combination  with  a 
substance  at  present  unknown.  Arbutin  brought  in  contact  with 
the  vapour  of  ammonia  and  with  atmosphere  air  assumes  a  slightly 
blueish  color.  In  contact  with  the  atmosphere  and  ammonia  it 
becomes  black.  The  ammoniacal  compound  thus  formed  is  com- 
posed of 
Qzo  H10  N3  O20 
Arctuvin  is  very  easily  changed  by  oxidizing  bodies,  and  colored 
brown  by  a  mere  cold  solution  of  bichromate  of  potash. 
Besides  gallic  acid  the  leaves  of  uva-ursi  contain  also  fat,  wax, 
and  chlorophylle,  a  small  proportion  of  sugar,  traces  of  an  ethereal 
oil,  and  small  proportions  of  a  substance  which,  if  heated  with 
diluted  sulphuric  or  muriatic  acid,  yields  an  ethereal  oil,  which 
readily  attracts  oxygen  from  the  air  and  becomes  dark  colored. 
This  oxydized  oil  has  the  formula^  C20  Hl6  05-  In  addition  to  these 
substances  the  aqueous  extract  of  the  leaves  contains  also  a  resin- 
ous substance,  which  is  obtained  by  heating  the  extract  with 
sulphuric  or  muriatic  acid,  and  purifying  by  solution  in  alcohol 
and  precipitation  with  water.  Its  composition  corresponds  with 
the  formula  Csn  H34  0,0=  H  O.  C30  Hfi4  (=8  C10  H8)— H30  +  O30 
-j-Cd0  H34  O30. — Pharm.  Jour.  Oct.  1,  1852,  from  Jlnnalen  d.  Chem 
und  Pharm.,  May,  1852,  p.  241. 
