1 84  Aril  of  Celastrus  Scandens.  {Km'l™\}m™' 
Chloroplasts,  as  their  name  indicates,  are  the  green  bodies  which 
impart  the  green  color  characteristic  of  leaves  and  stems.  The 
pigment  in  this  case  can  be  readily  extracted  by  means  of  such 
solvents  as  alcohol,  ether  and  chloroform,  while  the  matrix  remains 
behind  as  definitely  shaped,  colorless  masses  of  protoplasm.  The 
pigment  itself  may,  under  the  influence  of  various  factors,  external 
or  internal,  undergo  modifications  into  chemically  different  sub- 
stances, such  as  etiolin.  Chloroplasts  include  all  colored  chromato- 
phores  not  green.    The  distinction  is  quite  an  arbitrary  one. 
Chromoplasts  may  originate  from  leucoplasts  or  chloroplasts. 
The  latter  may  easily  be  observed  in  the  ripening  of  many  fruits. 
The  new  substances  resulting  from  this  metamorphosis  are  not  well 
known. 
The  red  color  of  fruits  undergoes  change  when  preserved  in  50 
per  cent,  alcohol,  due,  no  doubt,  to  oxidation  of  the  pigment. 
Those  of  Ilex  verticillata  become  brown ;  of  Magnolia  glauca,  dark 
brown ;  of  Lindera  benzoin,  almost  black ;  of  Berberis  Thunbergii, 
light  brown  ;  of  Crataegus  coccinea,  dark  brown.  In  rare  instances, 
however,  the  red  color  does  not  seem  to  be  affected  by  alcohol,  as, 
for  example,  the  berry  of  Arisaema  triphyllum  and  the  aril  of  the 
seed  of  Celastrus  scandens. 
A  microscopical  and  chemical  examination  of  the  latter  was 
undertaken.  The  section  showed  the  following  anatomical  struc- 
ture :  a  very  much  thickened  cuticle  of  a  lemon-yellow  color.  This, 
without  a  doubt,  affects  the  tint  which  has  some  yellow  in  it. 
Courchet2  states  that  the  color  of  certain  fruits  is  entirely  due  to 
the  impregnation  of  pigment  in  such  epidermal  thickenings,  and 
cites,  as  illustrations,  Solanum  macrocarpum  and  S.  racemiflorum. 
The  epidermis  consists  of  a  layer  of  small  cells  of  a  rather  uniform 
size.  The  chromatophores  within  these  are  very  conspicuous;  they 
are  bright  red  in  color,  and  in  form  very  narrowly  spindle-shaped, 
and  lie  parallel  to  each  other,  being  rather  closely  packed.  Below 
the  epidermis,  the  cells  constituting  the  rest  of  the  pulp  of  the  aril 
are  of  larger  dimensions,  and  the  chromatophores  seem  to  be  irreg- 
ularly scattered  through  the  cells. 
According  to  Zimmerman,3  the  pigments  of  chromatophores  found 
2  "  Recherches  sur  les  chromoleucites, "  Annates  de  Soc.  Nat.  Bot.,  Ser.  VII, 
T.  VII,  1888,  p.  301. 
3  Zimmerman,  "Botanical  Microtechnique."  Translated  by  James  Ellis 
Humphrey,  New  York,  1893. 
