THE MASTODON. 37 



many having succumbed through the extirpating power 

 of man, such as the bear, wolf, and other creatures in the 

 British Isles, and in this country. From the same cause the 

 buffalo, bear, and many others are gradually, and in some 

 cases rapidly, diminishing. This will not account for the 

 extinction of the mastodon, even admitting that man was 

 coeval, and assisted in its extermination. Vegetation ap- 

 pears to be the same as when the latest of these creatures 

 lived ; neither can it be safely concluded that the climate 

 may have undergone any remarkable alteration at the 

 period of its final extinction ; nor can it be attributed to 

 either a general or local inundation. It is true a species 

 may be overwhelmed by some calamity, such as a change 

 in climate, or an inundation, or scarcity of a particular 

 kind of food, or the sudden irruption of another genus. 

 There is no fixed law which determines the duration of any 

 species, for both single and whole groups of any genus 

 last for very unequal periods. An animal does not exist 

 because of its bodily strength alone, for mere bodily 

 strength does not give the victory in the battle of life. It 

 is a fact, which any one may notice, that the increase 

 of any group is constantly being checked by certain known 

 or else unperceived hostile agencies, and that the unknown 

 agencies are sufficient to cause rarity, and even final ex- 

 tinction. The continued increase of the existing elephant 

 in India and Africa, before man became a power there, 

 must have been checked by some cause. Dr. Falconer 

 was of opinion that their increase was checked chiefly by 

 blood-sucking insects which incessantly harrassed and 

 weakened them. It may then be inferred that the extinc- 

 tion of the mastodon was due to some imperceptible hos- 

 tile agency which first made it rare and then finally exter- 

 minated it. 



