142 EXTINCT SPECIES. 



more distinctly, between the vegetable and animal kingdoms, 

 each regarded in its entirety. Vegetables can only grow by 

 the assimilation of an element (carbon) which animals evolve 

 by respiration, as being a poison. Consideration of this fact 

 well-nigh forces the conclusion upon the mind if, indeed, 

 the conclusion be not inevitable that if through any vast 

 cataclysm animated life were to become suddenly extinct 

 throughout the world, vegetable life would languish until the 

 last traces of atmospheric carbon had become exhausted, and 

 then perish. 



In maintenance of her vital balance, through the operation 

 of some occult law, it often happens that animals that have 

 ceased to be ( obviously useful,' as taking part in a general 

 economy around them, are seen to die out. Whilst wolves 

 and elks roamed over Ireland, the magnificent Irish wolf-dog 

 was common. With the disappearance of wolves the breed 

 of wolf-dogs languished, and has ultimately become extinct. 

 As a matter of zoological curiosity, many an Irish gentleman 

 would have desired to perpetuate this gigantic and interest- 

 ing race of dogs ; but the operation the tendency to vital 

 equilibrium has been over-strong to be contravened: the 

 race of Irish wolf-dogs has fleeted away. Speaking now of 

 the huge Siberian mammoths, from which we diverged, faith 

 in Nature's balanced adaptation assures us that they died out 

 so soon as they ceased to be necessary as a compensation to 

 some unknown force in the vital economy. 



Spans and periods of time such as these, when compared 

 by the human mind with the normal period of individual 

 human existence, dwindle to nothingness, if we attempt to 

 make them the units of measurement in calculations involving 

 the duration of species. Perhaps the data are not available 

 for enabling the most careful investigator to come to an ap- 

 proximate conclusion as to the number of years that must 

 elapse before the race of existing elephants, African and 

 Indian, will become extinct; departing from the earth as 



