THE GREAT ICE AGE 15 



protective as concealing animals from one 

 another. 



So far I have not been able to find in books 

 about horses these appHcations of facts ac- 

 cepted by men of science, which are of use to 

 horsemen. In the light of such evidence the 

 close hogging of horse's manes needs recon- 

 sidering. 



PART II. THE GREAT ICE AGE. 



Unless a fellow can swim he has no business 

 to go out of his depth ; but if he minds his 

 business, he loses all the fun. 



It is the appHcation of these two principles 

 which leads me to a problem in the history of 

 the horse which nobody has solved. 



The species is native to the Americas, where 

 it became extinct. One theory of this 

 extinction imagines a germ, like that of 

 horse-sickness, whose range covered all lati- 

 tudes from tropic to sub-arctic. Such a 

 hearty microbe as that would seem unusual. 



The other theory relates to a disagreeable 

 change in the chmate, which overwhelmed the 

 drainage basin of the North Atlantic with a 

 field of massive ice. That seems conclusive 

 until one reflects that the Pacific slope of the 

 United States and the continent of South 

 America remained as warm as ever. The cold 



