Am.  Jour.  Pharm. 
June,  1899. 
Classification  of  Gums. 
271 
arabin.  They  are  almost  entirely  soluble  in  cold  water,  forming  a 
mucilage. 
Examples:  All  kinds  of  Acacia  gums,  mesquite,  Feronia,  or 
wood-apple,  Buchanania  and  acajou  gums. 
Sub-section  2.  Cherry  Group. — These  gums  consist  chiefly  of 
cerasin,  and  swell  in  cold  water,  forming  a  poor  mucilage. 
Examples :  Cherry,  peach  and  apple-tree  gums. 
Sub-section  j.  Tragacanth  Group. — The  gums  comprising  this 
group  consist  chiefly  of  bassorin,  and  swell  in  cold  water,  forming  a 
mucilage. 
Examples:  Tragacanth,  kuteera,  nopal,  Moringa  and  cocoanut 
gums. 
Sub-section  4..  Dextrin  Group. — The  representation  of  this  group 
consists  of  almost  pure  dextrin.  It  is  soluble  in  cold  water,  form- 
ing a  thick  viscous  solution  which  has  strong  adhesive  properties. 
Examples :  Dextrin,  British  gum  or  gommeline. 
Sub-section  5.  Seaweed  Group. — The  representative  of  this  group 
consists  chiefly  of  gelose.  It  forms  a  jelly  with  500  times  its  weight 
of  water. 
Example :  Japan  isinglass  from  Gelidium  corneum. 
SECTION  II.     TRUE  RESINS. 
Hard,  friable,  lustrous,  vegetable  substances,  externally  resemb- 
ling gums,  but  which  neither  dissolve  nor  soften  in  cold  water. 
They  burn  with  a  bright  smoky  flame,  contain  much  carbon,  but 
little  oxygen  and  no  nitrogen. 
Resins  are  not  definite  chemical  compounds,  but  are  complicated 
mixtures  of  the  resin  acids.    They  may  be  divided  into  six  groups. 
Sub-section  1.  Copal  Group.— These  resins  are  insoluble  in  ordin- 
ary solvents  unless  fused. 
Examples:  Amber,  animi  or  Zanzibar  copal,  Angola,  Sierra 
Leone,  pebble,  and  other  East  and  West  African  copals. 
Sub-section  2.  Dammar  Group. — The  resins  comprising  this 
group  are  more  or  less  soluble  in  ether,  chloroform,  benzol,  acetone, 
oil  of  turpentine  etc.,  and  are  almost  entirely  insoluble  in  alcohol. 
Examples:  Singapore  and  Batavian  dammars,  Kauri  or  Australian 
dammar,  and  American  copal  or  courbaril  resin. 
Sub-section  j.  Sandarac  Group. — These  resins  are  more  or  less 
soluble  in  alcohol  without  warming. 
