GUMS  AND  RESINS  OF  COMMERCE. 
225 
THE  GUMS  AND  RESINS  OF  COMMERCE. 
By  P.  L.  Simmonds. 
(Continued  from  page  142.) 
Mastic  is  derived  from  the  Pistaeia  lentiseus,  a  very  common 
shrub  in  various  parts  of  Northern  Africa,  where  it  is  sought  out 
for  its  resinous  produce. 
In  the  island  of  Chios,  where  the  tree  is  cultivated  for  the 
sake  of  the  resin  as  carefully  as  the  vine,  it  is  customary  to  make 
small  incisions  in  the  trunk  and  chief  branches,  about  the  end  of 
July.  From  these  clefts  the  sap,  which  gradually  thickens, 
exudes ;  it  hangs  in  larger  or  smaller  drops,  and  when  it  is  very 
abundant,  trickles  on  the  ground  and  dries  there.  It  is  detached 
from  the  tree  by  means  of  a  very  sharp  instrument ;  often  it  is 
caught  upon  cloths  spread  under  the  trees,  in  order  to  prevent 
any  soli  being  derived  by  contact  with  the  ground. 
The  largest  consumption  of  mastic  is  in  the  East,  where  it  is 
universally  chewed,  and  thence  derives  its  name.  It  is  asserted 
to  be  effectual  in  whitening  the  teeth,  strengthening  the  gums, 
and  sweetening  the  breath.  Mastic  is  also  used  in  the  prepara- 
tion of  the  finer  varnishes  for  pictures,  &c.  Owing  to  a  recent 
more  extensive  demand  for  France  and  deficient  supplies,  this 
gum  has  run  up  in  price  considerably,  being  now  vended  at  about 
Is.  6d.  the  ounce.  As  much  as  1500  cwt.  was  formerly  annually 
exported  from  Chios.  Dissolved  in  alcohol,  mastic  forms  a  very 
useful  cement.  It  is  obtained  in  Brazil,  from  the  Pistaeia  At- 
lantica,  and  in  Beloochistan  and  Affghanistan  from  other  varie- 
ties, P.  Kinjuh  and  P.  Qabulica. 
Most  of  the  Eucalyptus  genus  in  Australia  furnish  gum  in 
abundance,  particularly  the  red,  spotted,  and  white  gum,  the  iron 
and  stringy  bark  and  other  trees.  It  exudes  both  spontaneously 
and  in  larger  quantities  when  incisions  have  been  made  in  the 
trunk,  more  particularly  after  rain.  It  is  seen  in  masses  upon 
the  trunk,  but  its  particles  have  so  little  tenacity,  that  when  in  a 
concrete  form  any  attempt  to  detach  them  in  one  entire  lump 
fails,  and  it  crumbles  immediately  into  innumerable  fragments. 
This  gum  resin  has  a  strong  astringent  quality,  and  is  one  of 
the  varieties  of  the  kino  of  commerce. 
At  first  it  is  of  the  consistence  of  very  thick  syrup,  and  imme- 
diately after  rain  may  be  seen  flowing  from  an  incision  or  cleft 
15 
