454 
ON  HEMATOXYLIN. 
boiling.  When  saturated  with  sulphuric  acid,  the  fluid  becomes 
red  ;  but  white  hematoxylin  may  be  obtained  from  it  again. 
Carbonate  of  soda  behaves  in  the  same  way.  Yeast  (in  a  few 
days  at  86°  F.)  or  emulsine  (in  6  hours  at  113°  F.)  colors  the 
solution  of  the  substance  red  ;  it  then  contains  some  hemateine 
besides  hematoxylin.  Even  concentrated  muriatic  acid  effects 
no  essential  decomposition. 
Hematoxylin  reduces  Fehling's  solution.  It  diverts  the 
plane  of  polarization  strongly  to  the  right.  The  experiments 
show  for  1  grin.  C12  H14  O12  in  100  grms.  of  water,  with  a  length 
of  tube  of  200  millims.,  an  average  of  — 1°-85  to  the  right. 
Hematoxylin  is  soluble  in  a  cold  saturated  solution  of  borax 
until  it  comes  to  the  consistence  of  a  syrup.  From  a  solution  of 
this  kind  the  coloring  matter  cannot  be  recovered  in  a  crystal- 
line form  by  evaporation.  By  taking  up  hematoxylin  the 
solution  of  borax  loses  its  basic  reaction,  and  afterwards  has 
either  a  neutral  or  weakly  alkaline  reaction  upon  litmus-paper. 
The  borax  cannot  be  precipitated  from  such  a  solution  by  abso- 
lute alcohol,  or  by  a  mixture  of  absolute  alcohol  and  ether.  It 
exhibits  a  bluish  fluorescence. 
If  a  few  drops  of  muriatic  acid  be  let  fall  into  this  fluid,  a 
violent  movement  is  observed  in  it,  and  in  10 — 20  seconds  the 
entire  fluid  is  converted  into  a  dense  crystalline  mass.  The 
vessel  may  then  be  turned  upside  down,  without  the  mother- 
liquor  flowing  out.  But  within  a  few  hours  a  conversion  of  the 
crystals  commences ;  granular  crystals  make  their  appearance, 
and  settle  to  the  bottom  of  the  vessel,  and  above  them  there  is 
a  large  quantity  of  fluid.  These  granular  crystals  consist  of 
C32  H14  012+2HO.  Sulphuric  acid  and  acetic  acid  behave  in 
the  same  way  as  muriatic  acid.  If,  on  the  other  hand,  a  con- 
centrated solution  of  chloride  of  sodium  be  dropped  into  such  a 
solution,  each  drop  sinks  to  the  bottom  enveloped  in  an  amor- 
phous mass.  In  this  way  many  drops  of  solution  of  chloride  of 
sodium  may  be  seen  depositing  themselves  one  upon  the  other 
in  the  boracic  solution.  If  the  fluid  be  stirred  round,  a  slimy, 
emulsive  fluid  is  produced,  from  which  a  tenacious  mass  is  de- 
posited in  a  short  time.  This  posesses  a  silky  lustre,  which  is 
caused  by  small  cavities.  The  mass,  which  is  at  first  but  slightly 
colored,  soon  becomes  red,  as  it  is  very  sensitive  to  light  and 
