26 CONTROLLED NATURAL SELECTION 
it is of course quite impossible. A swan, for 
instance, must always be conspicuous against 
the sky. White, therefore, except in snow 
and to produce obliterative modelling, will 
render an animal conspicuous in Nature. 
Black.—As with white, it is possible to 
conceive of a black animal being invisible, 
for instance, against a black shadow : a rook 
sitting in the innermost recess of a thick 
forest would be difficult to see; but black 
shadows are almost unknown in Nature, 
especially cold black, such as is found in many 
animals. Shadows in Nature are invariably 
warm, because the objects in them are lit by 
the reflected light from surrounding warmly 
coloured objects. 
Animals coloured black, and especially cold 
black, must therefore be looked upon as con- 
spicuously coloured. Attention had again 
better be called to the fact, that it is not 
enough to study colour alone ; habits must also 
be taken into account. A black animal, living 
in dark forests and always shunning the light, 
cannot be compared in conspicuousness with 
a black animal which lives in open country, 
e.g. the female Blackbird with the Starling 
or Rook. 
Black therefore must be looked upon as 
