MISCELLANEOUS  CHEMICAL  OBSERVATIONS. 
311 
The  solution  thus  obtained  is  at  first  light  reddish-brown,  but  becomes 
as  dark  as  laudanum  by  age  and  exposure  to  light.  Of  the  precise  condi- 
tions concerned  in  producing  the  changes  in  Dr.  Plummer's  specimen  we  are 
not  aware.  Like  all  solutions  of  vegetable  matter,  containing  but  a  trace  of 
alcohol  as  in  this  case,  Mettauer's  solution  is  liable  to  cryptogamic  growths 
from  germs  derived  from  the  atmosphere,  especially  as  much  extractive 
matter  exists,  but  the  most  singular  part  of  the  matter  is  the  yellow  con- 
stituent of  the  sediment.  After  repeating  the  experiment  of  Dr.  Plummer, 
and  being  satisfied  that  his  observations  were  correct,  we  exhausted  a  part 
of  the  dark  brown  sediment  sent  to  us  in  the  letter,  with  alcohol  -835 
sp.  gr.,  and  allowed  it  to  evaporate  spontaneously.  As  the  tincture  con- 
centrated, a  deposition  of  crystalline  matter  occurred  in  crusts  ;  its  crys- 
talline character  is  easily  distinguishable  by  a  common  lens,  but  not  the 
form.  The  color  of  these  crusts,  when  dry,  is  deep  gamboge-colored.  When, 
however,  an  alcoholic  solution  is  suffered  to  evaporate  rapidly  on  a  surface 
the  color  is  bright  yellow.  The  alcoholic  solution  has  a  somewhat  bitter 
taste  ;  when  added  to  water,  if  concentrated,  it  forms  a  bright  yellow,  cloudy 
liquid.  Nitric  acid  added  to  this  produces  the  red  color,  but  this  character- 
istic is  best  observed  by  dropping  a  drop  on  a  watch  glass  and  spreading 
it  over  the  surface,  and  adding  a  drop  of  weak  nitric  acid,  when  instantly 
the  beautiful  carmine  red  is  developed.  This  substance  is  neutral,  is  not 
colored  red  by  alkalies  like  crysophanic  or  cryssammic  acids,  is  soluble  in 
ether,  but  much  less  so  than  in  alcohol,  and  its  ethereal  solution  is  rendered 
rose-colored  by  a  drop  of  nitric  acid ;  water  extracts  it  from  ether  by  agi- 
tation. It  is  insoluble  in  oil  of  turpentine.  When  this  substance  is  exposed 
on  a  piece  of  foil  to  a  red  heat,  it  puffs  up  and  affords  a  voluminous  char- 
coal :  and  on  burning  out  the  carbon,  a  gray  alkaline  ash  results  in  suffi- 
cient quantity  to  render  it  probable  that  the  yellow  substance  is  a  soda 
compound  of  an  organic  body,  (possibly  an  acid,)  which  in  its  free  state 
has  the  red  color.  The  fact,  however,  that  only  strong  acids  develop  this 
color  seems  opposed  to  this  view.  It  is  well  understood  that  carbonated 
alkalies  dissolve  aloin,  and  that  the  solution  in  contact  with  the  air  under- 
goes a  rapid  change,  becoming  darker,  owing  to  oxidation.  (See  Stenhouse, 
vol.  23,  p.  257,  of  this  Journal.)  It  is  probable,  therefore,  that  we  should 
look  to  this  reaction  long  continued  as  the  source  of  the  yellow  sub- 
stance observed  by  Dr.  Plummer.  We  have  examined  a  deposit  found 
in  Mettauer's  solution  two  months  old,  without  finding  any  indication  of 
this  substance.  We  hope  Dr.  Plummer  will  resume  the  subject  with  his 
more  abundant  material,  and  his  knowledge  of  all  the  circumstances,  and 
give  us  his  results  in  a  future  communication.  As  regards  the  errors  in 
Wharton  and  Stille,  those  of  our  readers  who  have  the  book  should  note 
them,  and  we  doubt  not  the  publisher  will  correct  the  next  edition. — 
Editor  Amer.  Jour.  Pharm.] 
