GEOLOGY. 249 



There is another admirable point in this scheme. The death and 

 decomposition of plant-eaters would have rendered the waters and air, 

 locally at least, destructive to life. It is well known that it is necessary 

 in an aquarium to have flesh-eaters along with the plant-eaters and 

 plants. And when in this way the living species are well balanced, 

 the water will remain pure, and the animals live on indefinitely. If 

 not so balanced, if an animal is left to decay, the waters become foul, 

 and often everything dies. Putrefaction and noxious chemical com- 

 binations follow death, because, in life, the constituents, carbon, hy- 

 drogen, nitrogen, and oxygen are in a constrained state, at the fur- 

 thest remove from what chemical forces alone can produce ; and hence, 

 when the restraint is taken off at death, the elements fly into new con- 

 ditions according to their affinities. Now animals, dying yearly by 

 myriads, are met at death by an arrangement which makes the dead 

 contribute anew to animal life as its aliment, and in this very process 

 the flesh ultimately comes out innocuous, and is at last so far changed 



v 7^1 



to the inorganic condition as to be the best fertilizers of plants. Part 

 of the process of getting rid of the great fleshy carcasses consists in 

 their minute subdivision by the feeding of larves of insects, and, fur- 

 ther, an infinitesimal division of the insect as the food of the infuso- 

 ria, which again may become the nutriment of larger animals, to 

 go the rounds once more. Bui the final result is, as stated, plant- 

 food, largely through the processes of digestion and excretion, but 

 part through the decomposition of animals that are too small and 

 readily dried up to prove offensive. 



Thus the carnivorous tribes were necessary to make the system of 

 life perfect. 



One word respecting the necessity of a check on the excessive 

 multiplication of individuals. Nature, as just now observed, is a sys- 

 tem of constantly varying conditions, of changing seasons, winds, 

 clouds ; of inconstancy, under law, in all forces and circumstances. 

 At the same time, the growth of a species requires the nicest adjust- 

 ment of special conditions in each case. On this account the repro- 

 ductive powers in species is in many cases excessively large, so that 

 the various accidents to which the eggs or young would be exposed 

 might not cause their extermination. This provision opened the way 

 for occasional excessive multiplication, and required a check from car- 

 nivorous races. 



(5.) Finally, could death be prevented in a system of living beings 

 in nature without constant miracles ? How should the earth be man- 

 aged to secure it against death ? It would be necessary to still the 

 waves, for they are throwing animals and plants on the coast to die ; 

 to still the winds, for they are ever destroying in some parts of their 

 course ; to still even the streams and rains. With winds and waves, 

 not only helpless animals and plants, but men's houses, ships, and 

 boats would now and then be destroyed, in spite of prudent precau- 

 tion and holy living. But if we still the waves, the winds, and the 

 streams, the earth would rot in the stagnation, and here again is 

 death ! 



We thus learn, that in life the fundamental idea of reproduction 

 implies death ; the processes of life are the processes simultaneously 

 of death ; the stability of the system of life requires death ; the veg- 



