ON  MANGOSTINE. 
381 
occur,  simply  because  one  of  the  substances  is  thus  removed  from 
the  field  of  action,  and  the  equilibrium  that  was  first  established 
is  thus  destroyed. 
VII.  That  consequently  there  is  a  fundamental  error  in  all 
attempts  to  determine  the  relative  strength  of  affinity  by  precipi- 
tation,— in  all  methods  of  quantitative  analysis  founded  on  the 
color  of  a  solution  in  which  colorless  salts  are  also  present, — and 
in  all  conclusions  as  to  what  substances  exist  in  a  solution,  drawn 
from  such  empirical  rules  as,  that  "  the  strongest  acid  combines 
with  the  strongest  base." — Chem.  Gazette,  April  16,  from  Proe. 
Royal  Society. 
ON  MANGOSTINE. 
By  Dr.  W.  Schmid. 
The  mangostine  tree  (Gfarcinia  mangostana),  which  is  culti- 
vated on  the  East  Indian  Islands,  furnishes  a  fruit  which  is  said 
to  possess  the  most  agreeable  flavor  of  all  tropical  fruits.  It  is 
of  the  form  of  a  berry  and  the  size  of  an  orange.  Dr.  Waitz,  a 
surgeon  in  the  Dutch  East  Indies,  has  employed  the  husk  of 
the  mango  in  fevers,  and  states  that  it  is  not  only  equal  to  bark, 
but  even  excels  this  when  used  in  the  fresh  state.  The  author 
has  accordingly  examined  these  husks. 
The  husks  used  were  dry,  of  a  brownish-red  color,  thick  and 
spongy,  with  an  astringent  taste,  and  contained  internally  a 
yellow,  semicrystalline  substance.  They  were  finely  powdered, 
and  repeatedly  extracted  with  water. 
The  watery  solution  contained  for  the  most  part  a  tannin, 
which  produced  a  black  color  with  iron.  The  residue  was  treated 
with  hot  alcohol,  which  completely  dissolved  the  yellow  crystalline 
matter.  The  fluid  was  filtered  and  left  standing  when  a  yellow 
amorphous  mass  separated  on  evaporation  ;  this  contained  the 
body  to  which  the  author  gives  the  name  of  mangostine,  mixed 
with  resin.  The  latter  is  very  difficult  of  separation  ;  the  best 
method  is  to  heat  the  filtered  alcoholic  solution  to  boiling,  and 
add  distilled  water  in  small  quantities  until  the  fluid  becomes 
opalescent.  The  resin,  which  is  but  sparingly  soluble  in  cold 
dilute  alcohol,  is  deposited  on  cooling  ;  the  mangostine  does  not 
separate  until  long  afterwards,  when  it  takes  the  form  of  small, 
