MICROSCOPIC VEGETABLES. 39 



In all this there is a most wise and beneficent 

 arrangement of Providence ; for, as Dr. Hooker 

 remarks, the universal prevalence of this invi- 

 sible vegetation throughout the South Polar 

 Ocean serves a great end. There is a marked 

 deficiency, he tells us, of the higher forms of 

 vegetation, and were it not for these Diatomacece 

 there would be no food for the aquatic animals ; 

 nor, supposing these animals to exist by preying 

 on each other, could the ocean waters, without 

 the Diatomacece, be purified of the carbonic acid 

 imparted to them by animals. 



" How wondrous is the scene ! where all is formed 

 With number, weight, and measure ; all designed 

 For some great end ! Where not alone the plant 

 Of stately growth, the herb of glorious hue, 

 Or food-full substance ; nor the labouring steed, 

 The herb and flock that feed us ; nor the mine 

 That yields us stores for elegance and arts ; 

 The sea that loads our table, and conveys 

 The wanderer, man, from clime to clime, with all 

 Those rolling spheres, that from on high shed down 

 Their kindly influence ; nor these alone 

 Which strike e'en eyes incurious, but each moss, 

 Each shell, each crawling insect holds a rank 

 Important in the scale of Him who framed 

 This scale of beings ; holds a rank, which, lost, 

 Would break the chain, and leave a gap behind, , 

 Which Nature's self would rue!" 



4. We think much of the changes produced 



