132  Notes  on  Some  Saps  and  Secretions.  { Al\{°Tch,m^m' 
Draccena  species.  The  dragon's  blood  of  Africa  has  been 
known  in  medicine  from  the  earliest  historical  times.  About  200 
chests  in  mass  or  blocks  come  into  London  yearly.  It  is  the  resi- 
nous exudation  of  several  different  plants,  is  dark  red-brown,  and, 
when  pulverized,  carmine  red,  without  taste  or  smell. 
The  African  from  Somali  land  is  yielded  by  D.  Schizantha,  and 
that  of  Socotra  by  D.  Ombet.  The  resin  exudes,  after  the  bark  has 
been  scraped,  in  about  a  fortnight.  The  Socotra  kind  is  exported 
from  Aden  to  Bombay. 
Dragon's  blood  was  formerly  referred  to  Draccena  Draco,  Lin.,  and 
Calamus  Draco,  Lin.  The  Sumatra  dragon's  blood  appears  in  com- 
merce in  the  form  of  reeds  or  sticks  about  a  foot  long  wrapped  in 
palm  leaves.  It  is,  sometimes,  employed  in  the  composition  of 
tooth-powders,  but  seldom  now  in  medicine.  Pterocarpns  Draco 
also  yields  dragon's  blood  ,and  other  species  kino. 
Epcrua  falcataf  Aubl.,  Dimorpha  falcata,  Swartz.  The  Wallaba 
resin  obtained  from  this  tree  in  Guiana  is  inflammable  and  gives  a 
bright  light. 
Its  styptic  and  curative  powers  in  cuts  and  bruises  are  well  appre- 
ciated by  the  Indians  and  other  natives  of  the  Colony.  An  oil 
obtained  from  the  wood  is  also  used  as  a  dressing  for  incised 
wounds. 
Eucalyptus  rostrata,  Schlechtendal.  An  exudation  from  this  tree 
is  a  most  invaluable  medicine  in  certain  disorders.  It  exudes  in  a 
fluid  state  from  the  bark,  and  in  some  instances  between  the  differ- 
ent layers  of  the  wood,  and  by  the  evaporation  of  the  watery  par- 
ticles by  which  it  is  held  in  solution,  it  concretes  into  a  beautiful 
ruby-colored  gum,  which,  when  exposed  for  a  length  of  time  to 
the  air  and  sun,  assumes  a  black  color  from  an  imperfect  oxidation, 
losing  at  the  same  time  its  astringency.  This  gum  is  an  original 
astringent  principle,  analogous  in  some  respects  to  tannin,  the  basis 
of  other  vegetable  astringents,  but  by  no  means  identical  with  that 
compound. 
It  is  more  effective  than  catechu,  or  Indian  kinos,  although  it  con- 
tains a  less  amount  of  astringent  matter. 
Dr.  J.  Sutherland,  of  Bathurst,  Australia,  in  a  communication  to 
my  Technologist  (vol.  3,  p.  69),  thus  speaks  of  it : 
"As  a  medicine,  it  is  a  more  powerful  astringent  than  any  in  our 
Pharmacopoeias,  and  justly  merits  a  place  among  the  legitimate  arti- 
