ON  THE  OIL  OF  THE  PURGING  NUT. 
141 
alkalies.  The  insoluble  disorganized  starch  no  longer  forms  a 
paste  with  hot  water,  but  by  the  action  of  acids  it  may  be  con- 
verted into  soluble  starch,  and  afterwards  into  dextrine.  The 
author's  memoir  contains  details  showing  the  insensible  passage 
of  insoluble  starch  to  the  state  of  soluble  starch. 
He  considers  that  his  experiments  leave  no  doubt  that  starch 
is  insoluble  in  all  its  parts,  although  formed  of  strata  of  different 
ages,  the  most  recent  being  the  most  readily  altered. 
The  following  properties  of  soluble  starch  serve  to  distinguish 
it  from  dextrine  : — 
1.  It  is  colored  blue  by  tincture  of  iodine. 
2.  Tannic  acid  produces  a  precipitate  with  it,  as  in  the  appa- 
rent solution  of  ordinary  starch. 
3.  It  causes  turbidity  in  lime  water,  and  produces  an  abundant 
precipitate  in  baryta  water.  Carbonic  acid  separates  it  un- 
changed from  its  baryta  compound. 
4.  Its  molecular  rotatory  power  is  much  greater,  but  in  the 
same  direction  ;  it  is  [«]e/=210°. 
The  solution  of  soluble  starch  passes  pretty  readily  through 
the  pores  of  an  animal  membrane. 
If  starch-paste  be  boiled  in  water  and  filtered,  the  filtrate  will 
not  contain  more  than  0-338  per  cent,  of  starch.  This  solution 
becomes  turbid  when  it  is  concentrated  on  the  water-bath  ;  the 
starch  separates,  and  the  liquid  when  filtered  does  not  contain 
more  dissolved  matter  than  before  the  evaporation.  A  solution 
of  soluble  starch,  on  the  contrary,  may  be  evaporated  to  a  syrupy 
consistence  without  turbidity. — London  Chem.  Graz  ,  from  Comp- 
tes  Rendus, 
ON  THE  OIL  OF  THE  PURGING  NUT  (CURCAS  PURGANS  1) 
By  J.  Bouis. 
A  plant  of  the  family  Eupliorhiacece,  which  occurs  in  the  West 
Indian  Islands,  produces  fruits  presenting  certain  analogies  with 
those  of  the  castor  oil  plant.  These  fruits,  known  as  purging 
nuts,  contain  a  kernel  which  tastes  like  a  nut,  but  the  very  active 
properties  of  which  are  soon  discovered  when  two  or  three  of 
them  have  been  eaten.    During  my  experiments,  several  people 
