CANTO i. PRODUCTION OF LIFE. 31 



Waves her bright tresses in the watery mass, 



And drinks with gelid gills the vital gas; 



Then broader leaves in shadowy files advance, 



Spread o'er the crystal flood their green expanse; 340 



And, as in air the adherent dew exhales, 



Court the warm sun, and breathe ethereal gales. 



" So still the Tadpole cleaves the watery vale 

 With balanc'd fins, and undulating tail; 



aerial leaves of vegetables do the office of lungs, by exposing a large 

 surface of vessels with their contained fluids to the influence of the 

 air; so these aquatic leaves answer a similar purpose like the gills of 

 fish, and perhaps gain from water a similar material. As the material 

 thus necessary to life seems to be more easily acquired from air than 

 from water, the subaquatic leaves of this plant and of sisymbrium, 

 oenanthe, ranunculus aquatilis, water crow-foot, and some others, 

 are cut into fine divisions to increase the surface, whilst those above 

 water are undivided ; see Botanic Garden, Vol. II. Canto IV. 1. 204, 

 Note. 



Few of the water plants of this country are used for economical 

 purposes, but the ranunculus fluviatilis may be worth cultivation; as 

 on the borders of the river Avon, near Ring-wood, the cottagers cut 

 this plant every morning in boats, almost all the year round, to feed 

 their cows, which appear in good condition, and give a due quantity 

 of milk; see a paper from Dr. Pultney in the Transactions of the 

 Linnean Society, Vol. V. 



So still the Tadpole, 1. 343. The transformation of the tadpole 

 from an aquatic animal into an aerial one is abundantly curious. 



