624  Resin  of  Myoporum  Platycarpum.  {A%Je0cU*im*rms 
the  interior  for  this  purpose.  It  would  probably  serve  as  a  con- 
stituent of  black  sealing-wax  ;  alone  it  is  too  soft  for  keeping  in  this 
climate. 
It  sometimes  occurs  in  great  quantities  on  the  stem,  is  hard  and 
brittle,  breaks  with  a  glassy  fracture  which  is  at  first  of  a  purple  or 
indigo  color,  but  becomes  brown  on  keeping.  Often  it  may  be  picked 
up  from  under  the  trees  in  rounded  or  globular  pieces. 
Two  samples  have  come  into  the  writer's  hands,  and  a  few  notes 
concerning  them  will  doubtless  be  interesting.  The  first,  from  the 
Lachlan  River,  New  South  Wales,  is  in  small  rounded  lumps  usually 
weathered  on  the  outside,  and  having  a  pleasant  empyreumatic  odor  ; 
these  are  of  a  dark  reddish-brown  color,  fly  with  the  slightest  touch 
of  the  pestle,  and  are  easily  powdered.  The  resin  has  a  bright  frac- 
ture, which  appears  almost  black,  but  shows  reddish-brown  at  the 
edges.  It  softens  even  with  the  warmth  of  the  hand,  and  if  kept  in  a 
bottle,  the  heat  of  an  average  summer  day  is  sufficient  to  fuse  pieces 
presenting  fresh  fractures. 
It  presents  some  external  resemblance  to  guaiacum  resin  (especi- 
ally when  that  substance  comes  to  market  in  small  lumps),  but  it  -is 
not  so  green  in  color  as  the  latter.  It  has  no  taste.  Cold  water 
has  no  effect  on  it,  but  if  the  water  be  heated  the  resin  melts  and 
floats,  forming  a  liquid  much  resembling  tar,  but  of  a  purplish- 
brown  color.  The  water  remains  clear,  colorless  and  almost 
odorless. 
Light  petroleum  dissolves  46*8  per  cent,  of  a  reddish -brown  resin, 
destitute  of  odor.  Alcohol  dissolves  from  the  residue  28*1  per  cent* 
of  a  deep  reddish-brown  resin,  which  is  almost  black  by  reflected 
light. 
The  residue  was  boiled  in  water  and  1*7  per  cent,  of  saline  matter 
was  extracted/  while  23*4  per  cent,  of  accidental  impurity  was  left 
behind.  This  is  of  a  chocolate  color,  and  under  a  lens  was  seen  to 
consist  of  a  little  ligneous  matter,  with  a  large  percentage  of  inor- 
ganic impurity.    It  was  quite  free  from  gum. 
Summary. 
a-Eesin  soluble  in  light  petroleum  46*8 
P-   "  "         alcohol  281 
Saline  matters   1*7 
A  ccidental  impurity  23*4 
100-0 
