8 LIFE ON THE EARTH. 



vast variety of plants, innumerable hosts of herbivo- 

 rous animals feed, and they minister to the appetites 

 of the Garni vora. It is conceivable that while the 

 plants remain unchanged, the Herbivora might 

 vary, or might become the prey of different flesh- 

 eaters ; but it is perhaps not conceivable that with 

 such an atmosphere as ours, under such conditions 

 as now obtain, there could be generally any great 

 variation in the relative total amount of vital energy 

 in plants, compared with animals. There seems also 

 a high degree of permanence in the relation of 

 Herbivora compared with Carnivora. Our marine 

 Cetacea might be replaced by Enaliosaurians ; our 

 Gasteropoda by Crustacea ; our fishes by Cephalo- 

 poda ; but the researches of geology seem to shew that 

 from the earliest periods, carnivora and herbivora, 

 plants and animals, have been combined into the same 

 general relations of mutual dependence as at present. 

 Subject to these conditions, life appears in all 

 the habitable spaces of the land, sea and air, filling 

 each with beings capable of enjoying their own 

 existence, and of ministering to the bodily wants 

 and intellectual longings of the one observing and 

 reflecting being to whom God has committed the 

 wonderful gift of thoughts which reach back beyond 

 the origin of his race, and stretch forward to a 

 brighter futurity. 



