CHEMICAL  RESEARCHES  ON  THE  MYRTLE  OF  AUSTRALIA.  213 
trunk  gives  rise  to  numerous  branches,  which  bear  an  abundance 
of  deep  green  elongated  persistent  leaves.  At  the  extremity  of 
the  young  branches,  and  at  the  insertion  of  the  leaves,  appear 
whitish  flowers,  to  which  succeed  pendant  fruit,  of  a  beautiful 
violet  red,  about  the  size  of  cherries,  but  of  an  elongated  form, 
and  an  agreeable,  slightly  sweet  and  acidulous  taste. 
The  tree,  during  nearly  six  months  of  the  year,  (from  Novem- 
ber to  March,)  is  covered  almost  continuously  with  flowers  and 
fruit — a  rare  thing  in  our  country  [Italy]. 
The  juice  obtained  by  expression  is  of  a  beautiful  violet  red ; 
its  taste  is  very  agreeable  and  slightly  acid ;  by  concentration 
and  repose,  it  deposits,  among  other  things,  a  crystalline  sub- 
stance which  is  cream  of  tartar ;  this  juice,  which  contains  glu- 
cose, ferments  at  the  ordinary  temperature  with  the  disengage- 
ment of  CO2  and  the  production  of  alcohol,  which  may  be 
obtained  from  it  by  distillation. 
The  coloring  matter  of  the  fruit  of  the  Australian  myrtle  is 
very  soluble  in  water  and  alcohol,  and  yet  better  in  a  mixture  of 
alcohol  and  ether,  although  it  does  not  dissolve  in  pure  ether. 
Purified  animal  black  retains  this  coloring  matter  as  it  does 
that  of  must  or  red  wine. 
The  action  of  the  air  and  of  fermentation  changes  the  violet 
red  color  of  the  juice  to  vinous  red  ;  the  ordinary  acids  redden 
it,  and  the  alkalies  give  a  beautiful  green  tint.  Paper  colored 
by  the  juice,  preserved  from  contact  with  the  air,  will  act  well  as 
test  paper  for  acids  and  alkalies. 
Reducing  agents,  such  as  alcoholic  ether,  sulphohydric  acid, 
or,  better,  nascent  hydrogen,  decolorize  the  juice  of  the  fruit 
of  the  myrtle,  but  afterwards,  when  exposed  to  the  air,  it 
regains  its  primitive  color. 
The  coloring  matter  of  wine  or  that  of  tournsol  comports 
itself  with  nascent  hydrogen  in  a  similar  manner. 
Red  wine  and  the  juice  of  the  Australian  myrtle  are  precipi- 
tated by  acetate  of  lead  ;  these  colored  precipitates,  when  they 
are  decomposed  by  diluted  chlorohydric  acid  in  the  presence  of 
ether,  afford  a  white  precipitate  of  chloride  of  lead,  beneath  two 
distinct  layers  of  liquid ;  the  lower  being  water  containing  the 
coloring  matter  ;  the  upper,  colorless  ether. 
The  juice  of  the  fruit  of  the  myrtle  of  Australia,  after  fer- 
