MATTER AND ENERGY. 57 



In the cataclysm which swept over this continent, the 

 horse had to go, though a re-introduction of the ani- 

 mal has been attended with satisfactory success. The 

 mollusks whose cretaceous envelopes are imbedded in 

 our hill-sides, did not perish through imperfections in 

 their organization, but through a subsidence of the 

 shallow seas in which they had thrived. There was 

 no application of the survival of the fittest dogma. 

 When a w r hale strands and dies, its death does not de- 

 pend upon a deficit in its organization, but upon an 

 accident. An increase of temperature amounting to 

 a few degrees would end organic life on our planet ; 

 as would also excess of cold, or the withdrawal of a 

 few degrees of heat. And it may be inferentially 

 stated that a return of our accustomed temperature 

 would be attended with a gradual peopling of the 

 earth again. When the conditions are favorable to 

 life, there will it be manifested. The attributes of 

 matter under favorable influences are all vivifying and 

 life-sustaining, but are restricted by incidental and ac- 

 cidental conditions. 



