MISCELLANEOUS  CHEMICAL  OBSERVATIONS.  309 
sooner  available  in  other  hands,  I  leave  the  further  disposi- 
tion of  this  curious  fact  to  thee. 
Another  interesting  matter  has  recently  occurred  to  me,  in 
the  case  of  Mettauer's  solution,  (the  compound  solution  of  aloes, 
for  the  preparation  of  which  a  formula  is  somewhere  given  in 
the  American  Journal  of  Pharmacy).  Having  obtained  very 
satisfactory  results  from  its  medicinal  use  for  years  past,  I  pre- 
pared several  gallons  of  it,  12  or  18  months  ago  ;  but  this 
spring,  I  found  the  surface  covered  with  a  white  mould  of  a  some- 
what saponaceous  character,  and  the  liquid  beneath  increased 
in  bitterness,  owing,  perhaps,  to  the  partial  removal  of  the  gly- 
cyrrhizine  by  the  molecular  action  which  generated  the  moodi- 
ness. After  decanting  the  solution,  I  found  at  the  bottom  of 
the  vessel  a  copious  blackish-brown  deposit,  of  a  coarse,  curdly 
appearance,  adhering  to  the  vessel  with  sufficient  firmness  to  ad- 
mit of  its  being  washed  repeatedly  with  water,  without  being  de- 
tached. The  discolored  water  was  wholly  free  from  the  bitter- 
ness of  aloes,  after  the  first  rinsing  of  the  deposit.  And  now 
for  some  enquiries: 
1.  What  formed  the  mould  ?  2.  What  remained  in  solution  ? 
And  3d,  What  constituted  the  deposit  ?  I  ascertained  only  that 
acids  caused  effervescence  with  the  mould,  indicating,  perhaps, 
the  presence  of  some  of  the  carbonate  of  soda  of  the  preparation. 
Aloes  was  evidently  held  in  the  solution,  judging  from  the  taste 
and  the  cathartic  action  of  the  liquid.  After  washing  the  de- 
posit, I  rubbed  some  of  it  into  a  thin  paste  with  water,  on  a 
white  pill-tile,  and  then  added  an  acid,  but  no  effervescence  fol- 
lowing, I  inferred  that  no  carbonate  of  soda  remained  in  the 
deposit.  But  instead  of  effervescence,  I  was  surprised  by  the 
immediate  appearance  of  a  beautiful  carmine  red.  A  very  thin 
film  of  the  paste,  with  a  drop  of  acid  at  one  end  of  it,  in  a  few 
moments  became  reddened  all  over,  say  to  the  extent  of  two 
inches.  This  was  probably  due  to  the  vapor  of  the  acid  passing 
over  it.  A  drop  of  strong  mineral  acid  dissolved  the  paste  where 
it  fell,  (immediately  after  the  generation  of  the  red  color,)  and 
only  formed  a  ring  of  red  at  its  margin  as  a  permanent  product. 
Dilute  mineral  acids  reddened,  but  did  not  dissolve  the  paste. 
Acetic  acid  produced  no  change. 
This  deposit,  when  dried,  is  friable  and  bitter  like  aloes,  (though 
not  to  the  same  degree  bitter)  and  of  similar  color  and  fracture. 
