Am*Aprnr'i8P84arm'}  Constitution  of  Chlorophyll.  219 
/3-Xanthophyll  =  xanthophyll  (Pringsheim).  Yellow  coloring  matter  of 
autumn  leaves  (perhaps  identical  with  a). 
y-Xanthophyll  =  yellow  coloring  matter  soluble  in  ether  ;  precipitated 
by  potash  from  cyanophyll. — Xanthin  (Dippel  ). — Xanthin  (G.  Kraus,  ex 
part. 
ef-Xanthophyll  —  Frcmy's  phylloxanthin,  separated  by  barium  hydroxide 
from  cyanophyll. 
•-Xanthophyll  =  yellow  coloring  matter  formed  in  Sachsse's  reaction 
(treatment  of  cyanophyll  solution  with  sodium);  permanent  in  benzene 
solution  (perhaps  identical  with  y). 
Xanthophyll  (G.  Kraus)  =  etiolin  (G.  Kraus). — Xanthophyll  (Sorby)  ex 
part. 
Erythrophyll  (Bougarel?)  =  chrysophyll  (Hartsen). — Borodin's  yellow 
crystals. — j-Xanthophyll  (Tschirch). 
Anthoxanthin  (Marquardt)  =  anthoxanthin  fPringsheimi. — Xanthin 
and  Xanthein  (Fremy  and  Cloez). 
Yellow  coloring  matters  of  flowers. — Jour.  Chem.  Soc,  1884,  p.  57-62. 
ON  THE  CONSTITUTION  OF  CHLOROPHYLL. 
By  Edward  Schunck,  F.R.S. 
A  Paper  read  before  the  Royal  Society,  December  20,  1883. 
An  examination  of  some  products  derived  from  chlorophyll,  which 
has  occupied  me  for  some  time,  has  led  to  the  question  of  the  true 
nature  and  constitution  of  chlorophyll,  a  question  on  which  widely 
different  opinions  prevail.  Without  entering  into  matters  which  con- 
cern the  physiologist  only,  it  may  be  said  that  to  the  chemist  chloro- 
phyll is  simply  an  organic  coloring-matter,  the  substance  to  which  the 
green  color  of  leaves  and  other  parts  of  plants  is  due.  Now  coloring- 
matters  are  of  three  kinds.  To  the  first  class  belong  such  as  occur 
ready  formed  and  in  a  free  state  in  vegetable  and  animal  organisms, 
such  as  the  coloring  matters  of  turmeric  and  safflower.  The  second 
class  comprises  those  that  are  formed  from  colorless  chromogens  by 
the  combined  action  of  alkalies  and  oxygen,  the  coloring-matters  of 
logwood  and  archil  being  well-known  examples  of  this  class.  These 
coloring-matters  change  rapidly  when  exposed  to  the  further  action  of 
oxygen  in  the  presence  of  alkali,  but  arc  quite  stable  when  in  con- 
tact with  acids.  The  third  class  consists  of  glucosides,  bodies  which 
do  not  undergo  any  considerable  change  under  the  influence  of  alkalies, 
but  are  rapidly  decomposed  when  acted  on  by  acids  or  ferments,  yield- 
ing, on  the  one  hand,  some  kind  of  glucose,  and,  on  the  other,  sub- 
