466 
VARIETIES. 
gon's  blood.  This  is  collected  from  the  seed-vessels  of  a  euphorbiaceous 
tree,  the  Roitlera  tinctoria  of  Koxburgh,  occurring  in  Arabia,  Eastern 
Africa,  and  various  parts  of  India,  The  Chinese  esteem  dragon's  blood 
highly.  It  is  obtained  in  Socotra,  from  the  Draccena  draco,  which  is  usually 
met  with  on  the  hills  at  the  elevation  of  800  to  2000  feet  above  the  level 
of  the  sea.  There  are  two  kinds  there,  and  the  best  is  of  a  dark  crimson 
color.  Jacquin  states  that  the  lump  dragon's  blood  is  the  produce  of 
Pterocarpus  draco,  but  this  is  very  questionable.  A  common  kind  in  the 
eastern  bazaars  is  the  produce  of  the  red  astringent  fleshy  fruit  of  the 
Calamus  draco,  or  by  incisions  in  the  stem,  or  natural  exudations  from 
various  parts  of  the  plant.  An  inferior  kind  is  obtained  by  boiling  the 
fruits.  In  the  Madras  bazaars,  dragon's  blood  ranges  in  price  from  £3 
to  £11  the  maund  of  82  lbs.,  according  to  quality. 
Dragon's  blood  was  the  cinnabar  of  the  ancient  Greeks.  In  the  time 
of  Dioscorides  the  opinion  prevailed  that  it  was  the  indurated  blood  of  a 
Iragon;  and  other  old  authors 'tell  us  that  the  tree  received  its  name  from 
having  the  figure  of  a  dragon  upon  the  fruit. 
A  red  juice  flows  from  the  wild  nutmeg  on  incisions  being  made  into 
the  bark.  This  hardens  into  laminated  resinous  pieces,  red  and  trans- 
parent, and  forms  a  variety  of  the  substance  known  in  commerce  under 
the  name  of  dragon's  blood.  Professor  Lindley  states,  on  the  authority 
of  Endlicher,  that  a  species  of  Myristica,  of  the  Phillippines,  yields  a 
crimson  juice,  which  is  collected  from  incisions  in  the  trunk,  and  used  as  a 
substitute  for  dragon's  blood,  under  the  name  of  Durgan. 
The  Icica  tribe,  lofty  trees  of  South  America,  produce  resinous  exuda- 
tions of  value  in  the  districts  where  the  trees  occur.  Of  these  I  have  speci- 
mens here  in  the  Carana  and  Tacamahaca  resins  ;  and  the  resins  of  Perama, 
another  dark  resin  from  Central  America.  The  Icica  Icicariba  or  Amyris 
elemifera,  produces  elemi,  which  resembles  olibanum  closely  in  its  proper- 
ties and  uses. 
Asphalte  is  manufactured  at  home  by  one  or  two  companies  to  the 
extent  of  two  or  three  thousand  tons  per  annum.  Small  imports  are 
received  from  America  and  the  Continent  for  the  use  of  varnish-makers, 
but  as  it  does  not  appear  in  the  trade  returns,  it  is  probably  included  with 
pitch,  of  which  we  receive  about  300  to  350  tons  yearly.  But  little  of  the 
genuine  Egyptian  asphalte  is  now  to  be  met  with.  There  is  one  prolific 
source  of  asphaltum  from  which  little  commercial  benefit  has  yet  been 
derived,  at  least  to  the  extent  to  which  it  is  susceptible,  and  that  is  the 
Pitch  Lake  of  Trinidad,  covering  a  surface  of  about  a  mile  in  length  by 
an  eighth  in  width.  Though  the  surface  is  generally  too  firm  to  receive  a 
foot-print — just  hard  enough  to  cut  readily  with  an  axe — there  are  places 
where  the  pitch  oozes  out  in  nearly  a  liquid  form.  But  the  pitch  is  not 
oonfinetj  to  this  locality.  There  are  masses  of  it  extending  wider  inland, 
and  in  several  points  it  reaches  to  the  sea-beach,  whence  it  is  shipped  in 
large  quantities  to  America,  and  some  of  the  West  India  Islands,  to  use  in 
