76 THE CAUSES WHICH PROPAGATE 



CHAPTER II. 



DISPLAY AND DANCES MATERIAL AGENTS IN REPRODUCTION AND 

 DISTRIBUTION — CORRESPONDING SENSE OF SIGHT. 



Those refreshing visitations of sleep, coincident with our passage 

 through the discordant shadow cone projected spaceward by our 

 revolving globe, are not participated in by the rest of the organic 

 creation, which in part have normal characters and sensorial 

 organs sharpened to render them nocturnal ; and as they approxi- 

 mate, the invertebrata become also less constitutionally capable of 

 extended exertion, so that the Articulate and Vegetable King- 

 doms, in their periods of recurring energy, mete the hours of the 

 eartVs revolution, and in the term of their existence record the 

 brief seasons of its circuit. These hours and seasons of transient 

 life are thus alike rendered conspicuous and grateful in the many- 

 coloured births of flowers, and by the gay masquerades, music, 

 and dances with which Insecta effect their reproduction : pageants 

 that surge and wane as the golden chariot- wheels move in their 

 fictitious track around the bright zodiacal lights — now kindling 

 into tumult at the sun-god's balmy approach, now subsiding to 

 melancholy as he sinks chilly from the zenith. 



So, too, at the momentary interception of the melodious 

 sunbeam by a flitting cloud, brilliant flies on the hedges, and 

 the frailer Dragon flies of the marsh land, faint as they sit on 

 the leaves, so as to be readily captured in the hand; and the 

 flitting butterflies, with other suctoria, remain motionless, as 

 enchanted; but no sooner does the source of light, heat, and 

 chemical action pass from its dull shroud, than both suctoria 

 and mandibulata renew their activity, and traverse with fresh 

 murmur the scented air. Indeed, it would seem as if the very 

 sense of fear originated in contractions induced by touch and 

 gloom ; and that sensitive plants, whose leaves fold and droop 



