ITS FLOEA AND FAUNA. 67 



mediately upon plants, or, if carnivorous, preys upon the 

 plant-feeders, and is thus also ultimately dependent on the 

 vegetable world for its subsistence. The law of circulation 

 and interdependence is complete ; and no portion of the 

 circle could be removed without a corresponding change in 

 the characters of the vegetable and animal kingdoms. Again, 

 many plants are dependent on the locomotive powers of 

 animals for their wider dispersion and increase ; while other 

 animals acquire a wider range through this new and in- 

 creased source of subsistence. Further, as many animals, 

 in their habits and organisation, are altogether fitted for an 

 arboreal existence,the destruction of the tree would involve 

 the destruction or non-existence of this peculiar organisa- 

 tion ; and as other creatures are specially fitted to live on 

 certain fruits, leaves, and roots, the disappearance of these 

 specific supplies would necessarily involve the annihilation 

 of the consumers. As in existing nature these and many 

 other similar adaptations are fixed and certain, and we may 

 safely reason from cause to effect and from effect to caus- 

 ation, so, in the ancient world, we may rely on similar ad- 

 justments reasoning from certain phases of plant and ani- 

 mal life to the conditions under which they must have ex- 

 isted, and from the presence of certain races of plants and 

 animals to the existence of other plants and animals to 

 which they were necessarily co-adapted. It is thus that 

 the study of the Past becomes hopeful, and Palaeontology 

 assumes the character of an inductive and reliable science. 

 The Present is ever the safest guide to the Past ; the Ex- 

 tinct is ever most clearly illuminated by the light reflected 

 from the Existing. 



