Concerning Eyes. 187 
possibly, also, in the minds of other species—with 
certain colours. Bright red seems the appropriate 
hue of anger—the poet Herbert even calls the rose 
‘‘angrie and brave” on account of its hue—and the 
red or orange certainly expresses resentment better 
than the dark eye. Even a very slight spontaneous 
variation in the colouring of the irides might give 
an advantage to an individual for natural selection 
to act on; for we can see in almost any living 
creature that not only in its perpetual metaphorical 
struggle for existence is its life safeguarded in many 
ways; but when protective resemblances, flight, 
and instincts of concealment all fail, and it is com- 
pelled to engage in a real struggle with a living 
adversary, it is provided for such occasions with 
another set of defences. Language and attitudes 
of defiance come into play ; feathers or hairs are 
erected ; beaks snap and strike, or teeth are gnashed, 
and the mouth foams or spits; the body puffs out ; 
wings are waved or feet stamped on the ground, 
and many other intimidating gestures of rage are 
practised. It is not possible to believe that the 
colouring of the crystal globes, towards which an 
opponent’s sight is first directed, and which most 
vividly exhibit the raging emotions within, can have 
been entirely neglected as a means of defence by 
the principle of selection in nature. For all these 
reasons I believe the bright-coloured eye is an 
improvement on the dark eye. 
Man has been very little improved in this 
direction, the dark eye, except in the north of 
