CANTO i. PRODUCTION OF LIFE. 27 



First forms minute, unseen by spheric glass, 



Move on the mud, or pierce the watery mass; 



These, as successive generations bloom, 



New powers acquire, and larger limbs assume; 300 



Whence countless groups of vegetation spring, 



And breathing realms of fin, and feet, and wing. 



" Thus the tall Oak, the giant of the wood, 

 Which bears Britannia's thunders on the flood; 

 The Whale, unmeasured monster of the main, 

 The lordly Lion, monarch of the plain, 

 The Eagle soaring in the realms of air, 

 Whose eye undazzled drinks the solar glare, 



nous bag, which contains air, at the broad end of the egg; and in this 

 the chick in the egg differs from the fetus in the womb, as there is 

 in the egg no circulating maternal blood for the insertion of the 

 extremities of its respiratory vessels, and in this also I suspect that 

 the eggs of birds differ from the spawn of fish; which latter is im- 

 mersed in water, and which has probably the extremities of its respi- 

 ratory organ inserted into the soft membrane which covers it, and is 

 in contact with the water. 



First forms minute, 1. 297. See Additional Note I. on Sponta- 

 neous Vitality. 



