ALOINE. 
145 
was  added  to  slight  acidulation — a  resinous  precipitate  was 
formed,  which  caused  filtration  to  proceed  with  great  difficulty. 
The  addition  of  finely-powdered  wood  charcoal  would  have  much 
facilitated  it.  Washed  arrowroot  has  not  so  good  an  effect. 
The  solution  was,  after  filtration,  evaporated  by  a  water-bath  to 
the  consistence  of  syrup,  transferred  to  a  small  basin  covered  by 
bibulous  paper,  and  set  aside  on  a  shelf  of  the  laboratory. 
In  less  than  a  week  crystallization  had  commenced  ;  in  a  fort- 
night it  had  become  a  mass  of  crystals,  that  had  grown  irregu- 
larly, considerably  above  the  level  of  the  liquid.  They  were 
transferred  to  coarse  blotting-paper,  allowed  to  drain  a  day  or 
two,  then  shifted  to  another  piece,  wrapped  in  it,  and  gently 
pressed  by  means  of  a  weight.  Cautiously  proceeding  thus,  they 
were  at  last  powerfully  pressed  with  a  screw,  and  presented  the 
appearance  of  a  brown-colored  brittle  mass.  This  was  dissolved 
in  as  small  a  quantity  as  possible  of  boiling  water,  allowed  a  few 
days  to  crystallize,  and  then  treated  as  before.  A  third  crys- 
tallization sufficed  to  procure  crystals  of  a  pale  lemon  color  (pure 
aloine),  which  weighed  when  dry  48  grains — 10  per  cent,  of  the 
aloes  employed.  I  found  it  was  necessary  to  dry  them  in  the 
compressed  mass,  closely  wrapped  in  blotting-paper,  and  at  a 
temperature  of  about  1O0.  The  surface  and  edges  only  were 
oxidized,  and  were  removed  before  powdering  and  weighing. 
When  thoroughly  dry,  it  does  not  appear  to  undergo  any  change 
at  the  ordinary  temperature.  When  damp,  however,  and  at 
the  same  time  exposed  to  heat,  it  oxidized  rapidly,  and  could  be 
made  to  assume  almost  exactly  the  appearance  of  the  aloes 
whence  it  was  originally  taken, 
I  am  therefore  of  opinion  that  it  is  not  to  their  possessing  a 
vitreous  character,  but  to  circumstances  connected  with  the  com- 
position of  the  original  juice  from  which  they  are  made,  that  the 
various  degrees  of  facility  with  which  aloine  may  be  obtained 
from  them  is  due,  and  that  aloine  may  be  procured  from  all  that 
have  not  been  actually  carbonized. 
With  respect  to  its  purgative  power,  of  which  M.  Robiquet 
denies  it  the  possession,  and  which,  to  cause  such  variety  of 
opinion,  must  at  least  be  very  uncertain,  I  think  with  M.  R.  that 
it  is  only  when  oxidized  it  possesses  that  power.  It  would  be 
impossible  for  it  to  pass  through  the  intestines  without  some  de- 
10 
