Am.  Jour.  Pharm. 
June,  1884. 
Dragon's  Blood. 
327 
RED  RESINS  KNOWN  AS  DRAGON'S  BLOOD. 
By  J.  J.  Dobbie  and  G.  G.  Henderson. 
Besides  the  red  resins  from  Pterocarpus  Draco  and  Oroton  Draco, 
there  are  three  different  recognized  kinds  of  dragon's  blood,  one  from 
the  East  Indies,  Calamus  Draco  ;  one  from  Socotra,  and  one  from  the 
Canary  Islands,  Dracoena  Draco.  The  first  of  these  is  the  only  one 
that  has  been  fully  described,  but  the  results  are  not  concordant ;  this 
is  due  apparently  to  the  researches  having  been  carried  out  on  different 
substances.  The  authors  have  now  investigated  this  subject,  and  have 
examined  several  varieties  of  the  so-called  dragon's  blood,  which  they 
find  can  be  arranged  in  four  distinct  groups :  1.  Those  which  dissolve 
completely  in  chloroform,  carbon  bisulphide,  and  benzene ;  2.  Those 
soluble  in  chloroform,  but  insoluble  in  carbon  bisulphide  and  benzene ; 
3.  Those  soluble  in  chloroform  and  benzene,  and  partly  in  carbon 
bisulphide;  and  4.  Those  which  are  insoluble  in  all  three  reagents. 
The  accuracy  of  this  classification  is  supported  by  the  physical  proper- 
ties of  the  resins  and  their  behavior  towards  reagents,  and  it  is  evident, 
therefore,  that  there  were  four  different  kinds  of  resins  under  examina- 
tion. All  the  resins  dissolve  to  a  small  extent  in  boiling  water,  those 
of  Class  4  being  rather  more  soluble  than  the  others  ;  they  are  all  freely 
soluble  in  alcohol,  ether,  oil  of  cloves,  and  glacial  acetic  acid,  leaving 
a  variable  amount  of  insoluble  matter,  which  usually  consists  of  vege- 
table tissue,  sand,  etc.  They  are  all  slightly  soluble  also  in  hydrochloric 
acid,  those  of  Class  2  being  the  most  soluble ;  ammonia  reprecipitates 
them  from  this  solution.  The  aqueous  and  alcoholic  solutions  have 
an  acid  reaction.  When  treated  with  sodium  hydroxide,  the  resins 
effervesce  and  emit  an  odor  like  that  of  rhubarb.  Ammonia  forms  a 
clear  mixture  with  the  alcoholic  solutions.  The  resins  were  carefully 
purified  by  means  of  ether,  and  then  powdered ;  the  results  of  the  indi- 
vidual class  examinations  may  be  thus  summed  up :  Resin,  1,  brick- 
red,  melting  at  about  80°,  when  decomposed  by  heat  gives  off  very 
irritating  red  fumes.  It  dissolves  readily  with  an  orange-red  color  in 
alcohol,  ether,  chloroform,  carbon  bisulphide,  and  benzene,  but  with 
difficulty  in  boiling  caustic  soda,  ammonia,  sodium  carbonate,  and  with 
great  difficulty  in  lime-water,  whilst,  in  the  cold,  it  is  scarcely  soluble 
in  the  first  two  and  insoluble  in  the  last  two  of  the  latter  reagents. 
The  ammonia  solution  is  reddish -yellow,  and  a  portion  of  the  resin  is 
not  dissolved.    The  alcoholic  solution  gives  a  brown-red  precipitate 
