'""•s^pt.'.fsT""-}  Spurious  Gums.  453 
• 
Recorded  analyses  of  African  bdellium  differ  widely.  Guibourt,  in 
his  fourth  edition  of     Drogues  Simples,"  gives — 
Resin,        .              .              .              .              .              .  59*0 
Soluble  gum,      .               .               .               .               .  9*2 
Bassorin,     ......  30'6 
Volatile  oil  and  loss,          ....  1-2 
lOO'O 
while  Planchon,  in  the  seventh  edition  of  the  same  woric,  says  it  yields 
70*3  per  cent,  to  boiling  alcohol,  the  rest  being  a  gum  completely  soluble 
in  water, 
3.  Opaque  tasteless  gum-resin  occurs  in  large  tears  with  smooth  sur- 
face, is  very  hard,  has  a  dull  waxy  fracture  and  is  almost  devoid  of 
color,  odor  and  taste.  Several  pieces  have  papery  bark  attached,  and 
two  or  three  large  tears  were  found  imbedded  in  fine  specimens  of 
myrrh,  suggesting  their  exudation  from  the  same  trunk  underabnormal 
conditions,  but  the  gum  and  resin  differ  materially  from  those  of 
myrrh. 
Triturated  with  water  this  substance  gives  a  very  slightly  milky 
solution  and  a  copious  sediment.  It  is  soft  and  adhesive  between  the 
teeth. 
Alcohol  dissolves  about  60  per  cent.  ;  the  residue  is  almost  entirely 
soluble  in  water. 
.  In  the  air-bath  a  portion  lost  7*6  per  cent,  at  ioo°C.,  and  when 
ignited  left  '865  per  cent,  of  ash,  chiefly  calcic  carbonate. 
The  tincture  (i  in  6)  is  not  precipitated  by  bromine  or  plumbic 
acetate,  or  changed  by  ferric  chloride  or  lead  subacetate  ;  it  becomes 
milky  with  water. 
The  mucilage  is  not  affected  by  neutral  acetate  of  lead  and  only 
slightly  precipitated  by  subacetate. 
Composition  of  opaque  tasteless  gum-resin  : 
Soluble  in  alcohol  (by  difference),           .              .              .  60-54 
Gum  soluble  in  water        ....  30-32 
Gum  insoluble  in  water,           ....  1-54 
Moisture,          .              .             .              .             .  7-60 
lOQ-OO 
4.  Yellow  Tasteless  Gum- Resin. — This  is  at  once  recognized  by  the 
peculiar  powdery  yellow  appearance  of  the  surface  of  the  tears,  which 
are  mostly  small  and  irregular.  It  is  yellowish-white  in  color,  almost 
devoid  of  taste  and  odor,  hard  and  easily  powdered  ;   resinous  when 
