166  RED  COLORING  MATTER  OF  CALURUS  AURICEPS. 
mixture  warmed  and  filtered.  The  filtrate,  still  containing  excess 
of  ammonia,  was  acidified  and  evaporated  to  dryness,  and  cal- 
cined to  expel  organic  matter.  The  residue,  after  fusion  with  a 
little  pure  carbonate  of  potash,  was  dissolved  in  hydrochloric 
acid  and  alumina  reprecipitated  by  ammonia  free  from  organic 
impurity.  On  determining  its  amount  by  weight  it  yielded  0-31 
gr.  of  alumina.  About  4  grs.  of  alumina  were  precipitated  in 
the  first  stage.  Hence,  any  results  got  by  the  use  of  ammonia 
from  which  organic  matter,  at  least,  has  not  been  removed,  are 
apt  to  be  vitiated  and  not  to  be  relied  upon. — London  Chemist, 
December,  1857. 
ON  THE  RED  COLORING  MATTER  OF  THE  FEATHERS  OF 
CALURUS  AURICEPS. 
By  M.  An.  Bogdonow,  of  Moscow. 
The  attention  of  ornithologists  has  been  of  late  years  much 
directed  to  two  questions  of  the  greatest  importance  and  interest 
in  the  science  of  birds :  the  cause  of  the  coloration  of  the 
feathers,  the  absence  of  color  on  the  one  hand,  and  on  the  other, 
the  influence  of  external  agents  on  the  coloration  of  beings,  the 
stability  of  varieties,  and  their  signification  in  classification. 
The  last  question  is  evidently  closely  allied  to  the  first. 
Having  found  that  chemical  works  contained  nothing  relative 
to  the  coloring  matter  of  feathers  we  resolved  to  seek  for  it  our- 
selves. Fortunately,  our  studies  on  the  chemical  characters  of 
the  horny  substance  and  the  action  of  different  chemical  agents 
on  this  substance  gave  us  a  means  of  extracting  and  isolating 
the  coloring  matter,  although  this  means  only  enabled  us  to 
succeed  with  certain  colors.  This  process  forms  the  subject  of 
the  present  article. 
The  horny  substance  forming  the  base  of  the  feather  is  soluble 
only  in  caustic  potassa,  sulphuric  acid,  and  Papin's  digester ;  it 
swells  in  acetic  acid,  and  water ;  alcohol  and  ether  have  no  in- 
fluence on  it.  By  modifying  the  effects  of  these  agents  on 
feathers  of  various  colors  and  constitutions,  we  for  a  long  time 
obtained  no  result,  until,  amongst  these  combinations,  we  put  red 
feathers  into  boiling  alcohol.    Our  process  of  isolating  the  red 
