186 ANIMALS or THE PAST 



such accidents may occur is familiar to us by the damage 

 wrought in Florida and other Southern States by the 

 unwonted severity of the winters of 1893, 1895, and 

 1899. 



If any group of forest trees was destroyed in the 

 manner suggested by Professor Shaler, the effects would 

 be felt by various plants and animals. In the first 

 place, the insects that fed on these trees would be forced 

 to seek another source of food and would be brought 

 into a silent struggle with forms already in possession, 

 while the destruction of one set of plants would be to the 

 advantage of those with which they came into competi- 

 tion and to the disadvantage of vegetation that was 

 protected by the shade. Finally, these changed condi- 

 tions would react in various ways on the smaller birds 

 and mammals, the general effect being, to use a well- 

 worn simile, that like of casting a stone into a quiet pool 

 and setting in motion ripples that sooner or later reach 

 to every part of the margin. 



It is scarcely necessary to warn the reader that for the 

 most part this is purely conjectural, for from the nature 

 of the case it is bound to be so, as is the suggestion that 

 the horse was exterminated in North America by the 

 tsetse fly. But it is one of the characteristics of edu- 

 cated man that he wishes to know the why and where- 

 fore of everything, and is in a condition of mental un- 

 happiness until he has at least formulated some 

 theory which seems to harmonize with the visible facts. 

 And from the few glimpses we get of the extinction of 

 animals from natural causes we must formulate a 

 theory to fit the continued extermination that has been 

 taking place ever since living beings came into the world 

 and were pitted against one another and against then- 

 surroundings in the silent and ceaseless struggle for 

 existence. 



