2 So The Naturalist in La Plata. 



and is very simple indeed, and, like that of Dr. 

 Wallace 1 with regard to colour and ornaments, 

 covers the whole of the facts. We see that the 

 inferior animals, when the conditions of life are 

 favourable, are subject to periodical fits of gladness, 

 affecting them powerfully and standing out in vivid 

 contrast to their ordinary temper. And we know 

 what this feeling is this periodic intense elation 

 which even civilized man occasionally experiences 

 when in perfect health, more especially when young. 

 There are moments when he is mad with joy, when 

 he cannot keep still, when his impulse is to sing and 

 shout aloud and laugh at nothing, to run and leap 

 and exert himself in some extravagant way. Among 

 the heavier mammalians the feeling is manifested in 

 loud noises, bellowings and screamings, and in lum- 

 bering, uncouth motions throwing up of heels, pre- 

 tended panics, and ponderous mock battles. 



In smaller and livelier animals, with greater 

 celerity and certitude in their motions, the feeling 

 shows itself in more regular and often in more com- 

 plex ways. Thus, FelidaB when young, and, in very 

 agile, sprightly species like the Puma, throughout 

 life, simulate all the actions of an animal hunting 

 its prey sudden, intense excitement of discovery, 

 concealment, gradual advance, masked by interven- 



1 It is curious to find that Dr. Wallace's idea about colour 

 has been independently hit upon by Ruskin. Of stones he writes 

 in Frondes Agrestis : " I have often had occasion to allude to 

 the apparent connection of brilliancy of colour with vigour of life 

 and purity of substance. This is pre-eminently the case in the 

 mineral kingdom. The perfection with which the particles of 

 any substance unite in crystallization, conesponds in that king- 

 dom to the vital power in organic nature." 



