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Classification  of  Gums. 
Am.  Jour.  Pharm. 
June,  18G9. 
Examples:  Sandarao,  mastic,  Manila  copal,  the  black,  white  and 
sal  dammars  of  India,  and  guaiacum  resin. 
Sub-section  4.  Colophony  Group. — These  resins  are  obtained  in 
the  distillation  of  crude  turpentine  or  other  oleo- resins,  or  they  may- 
be natural  products  which  have  lost  their  volatile  oil  through  evap- 
oration.   They  are  entirely  soluble  in  alcohol. 
Examples:  Common  resin  or  colophony. 
Sub-section  5.  Benzoin  Group. — The  resins  of  this  group  are  solu- 
ble in  alcohol  and  contain  benzoic  or  cinnamic  acids  or  yield  them 
when  subjected  to  heat. 
Examples:  Benzoin,  dragon's-blood  from  the  East  Indies,  yellow 
and  red  grass-tree  gums  or  acaroid  resin. 
Sub-section  6.  Lac  Group. — This  group  includes  the  resinous 
incrustation,  as  well  as  the  purified  products  obtained  therefrom, 
which  is  found  on  the  twigs  of  many  species  of  trees,  and  is  elabor- 
ated from  the  sap  by  the  female  of  the  lac  insect  (Coccus  lacca). 
They  are  partially  soluble  in  alcohol,  forming  a  turbid  solution. 
Examples:  Stick  lac,  seed  lac,  shellac,  button  and  garnet  lac. 
SECTION  III.     INODOROUS  GUM-RESINS. 
Plant  exudations,  having  no  pronounced  odor,  and  which  consist 
essentially  of  gum  and  resin  associated  together  in  various  propor- 
tions, sometimes  accompanied  by  waxy  matters.  They  form  an 
emulsion  with  water  and  contain  no  volatile  oil. 
Examples:  Gamboge,  South  American  hog-gum. 
SECTION  IV.     ODOROUS  GUM-RESINS. 
Plant  exudations,  composed  of  mixtures  of  gum,  resin  and  vola- 
tile oil  in  varying  proportions.  They  have  a  distinctive  odor,  which 
may  be  fcetid  or  fragrant  in  character. 
Sub-section  1.  Asafoetida  Group. — This  group  includes  gum-resins 
having  a  fetid  or  more  or  less  disagreeable  odor.  The  most  im- 
portant of  them  are  yielded  by  plants  belonging  to  the  order  Urn- 
belliferae. 
Examples:  Asafcetida,  galbanum,  ammoniacum,  opopanax  and 
"cumbi"  or  Gardenia  resin. 
Sub-section  2.  Myrrh  Group. — These  are  gum- resins  having  a 
more  or  less  fragrant  odor.  The  majority  of  them  are  yielded  by 
plants  belonging  to  the  order  Burseraceae. 
Examples  :    Myrrh,  bdellium,  olibanum  and  "  gomart  "  resin. 
