ECONOMY OF NUTRITIVE MATTER. G3 



which sport in countless myriads their ephemeral 

 existence within the ample regionsof every drop. 

 Yet even these are still qualified to fulfil other 

 objects in a more distant and far wider sphere ; 

 for, borne along, in the course of time, by the 

 rivers into which they pass, they are at length 

 conveyed into the sea, the great receptacle of all 

 the particles that are detached from the objects 

 on land. Here also they float not uselessly in 

 the vast abyss, but contribute to maintain in ex- 

 istence incalculable hosts of animal beings, which 

 people every portion of the wide expanse of 

 ocean, and which rise in regular gradation from 

 the microscopic monad, and scarcely visible 

 medusa,* through endless tribes of mollusca, and 

 of fishes, up to the huge Leviathan of the deep. 



Not even are these portions of organic matter, 

 which, in the course of decomposition, escape in 

 the form of gases, and are widely diffused through 

 the atmosphere, wholly lost for the uses of living 

 nature : for, in course of time, they, also, as we 

 have seen, re-enter into the vegetable system, 

 resuming the solid form, and reappearing as 

 organic products, destined again to run through 



* The immensity of the numbers of these microscopic medusae, 

 which people every region of the ocean, may be judged of from 

 the phenomenon of the phosphorescent light which is so fre- 

 quently exhibited by the sea, when agitated, and which, as I have 

 already observed, is found to arise from the presence of an incal- 

 culable multitude of these minute animals. 



