THE HUMAN SKIN. 99 



down upon a whitlow. Friction against a hard sub- 

 stance brings about this extra thickness and hardness ; 

 the young ladies who handle silk, woollen or cotton 

 textures all day long in shops have soft hands. Like 

 begets like ; and hard roads make hard feet for 

 horses, in spite of all superstition to the contrary. 

 The writer has more than a quarter of a century of 

 experience and practice with unshod horses in large 

 numbers. He has, therefore, no theory about the 

 matter, constructed, as may perhaps be imagined, 

 upon the quotations he has so freely used from the 

 writings of scientific, professional, and practical 

 authorities. 



H 2 



