564     TRANSFORMATION  OF  SOLUBLE  INTO  INSOLUBLE  GUMS. 
more  quickly  than  by  way  of  the  stomach,  that  its  action  in  this 
case  is  almost  exclusively  narcotic,  and  that  it  killed  a  rabbit  in 
37  minutes,  in  the  dose  of  0-02  gr.,  and  a  vigorous  dog  in  an 
hour  and  22  minutes,  in  the  dose  of  004  gr. 
NOTE  ON  THE  TRANSFORMATION  OF  SOLUBLE  GUMS  INTO 
INSOLUBLE  GUMS. 
By  M.  A.  Gelis. 
Although  gummy  matters  are  found  in  almost  all  plants,  they 
have  hitherto  been  the  subject  of  very  few  observations.  M. 
Gue'rin  Vary  is  almost  the  only  chemist  who  has  studied  in  a 
consecutive  manner  their  analysis  and  their  transformations.  He 
has  extracted  from  natural  gums  various  substances,  all  of  which 
possess  the  property  of  giving  mucic  acid  when  they  are  heated 
with  nitric  acid,  and  from  all  these  substances  he  formed  a  genus 
whose  species  are — Arabine,  Bassorine,  and  Cerasine.  Eerzelius 
has  not  adopted  this  division  ;  he  gives  the  name  of  gum  only  to 
matter  soluble  in  water,  which  forms  almost  the  whole  of  gum 
Arabic  and  gum  Senegal,  and  he  separates,  under  the  designa- 
tion of  vegetable  mucilage,  the  principle  insoluble  in  water, 
which  communicates  to  the  gum  of  Bassora,  to  gum  tragacanth, 
to  linseed,  and  to  quince-seed,  &c,  the  property  of  swelling  up 
very  considerably  in  this  liquid. 
The  analogy  which  exists  between  gums  and  starch,  and  the  ap- 
parent resemblance  which  is  observed  between  paste  and  vege- 
table mucilage,  led  us  to  think  that  this  property  of  swelling  up 
in  water  which  certain  gummy  matters  possess,  was  due  to  a  kind 
of  organisation  existing,  in  different  degrees,  in  a  different  species. 
According  to  this  view,  and  by  establishing,  for  gum,  a  series 
parallel  to  that  of  starch,  we  should  be  in  some  measure  forced 
to  consider  cerasine  and  bassorine  as  representatives  of  organised 
fecula,  and  arabine  as  the  analogue  of  dextrine.  The  observa- 
tion which  forms  the  subject  of  this  note  is  of  a  nature  to  lead 
us  to  the  contrary  opinion,  since,  by  heating  gum  Arabic— that 
is  to  say,  by  placing  it  in  conditions  of  disorganisation,  I  have 
converted  it  into  a  principle  possessing  all  the  properties  of  the 
mucilage  of  Eerzelius. 
