SYMPTOMS AND CAUSES OF COKN. 391 



most frequently found in the inner heel when the toe is 

 turned outwards and vice versa. Weak, low, badly formed or 

 contracted heels are all potent causes. Corns are also very 

 common as a disease secondary to side bone. ' Dropped ' soles 

 often exhibit corns, the heels of the shoe being liable to press 

 on, or even become embedded in, the sole at the point of the 

 heel. 



The external caioses are many. First come faulty prepara- 

 tion of the hoof, bad shoeing, and reckless paring of broad 

 flat hoofs ; then follow weakening of the heels, sole, bars, and 

 frog in all other forms of hoof, at the same time that the 

 toe is left too long ; unequal paring of one side of the hoof 

 destroying the level character of the tread ; excessive trimming 

 of the sole and bars in order to give the appearance of a strong 

 hoof, and cutting away the bars. Amongst faulty shoes may 

 be mentioned those which are either too short, too far set 

 under the hoof or nailed on across it, and shoes which incom- 

 pletely cover the bearing surface or in which the bearing 

 surface itself inclines inwards at the heels. These confine the 

 expansion of the hoof. In flat and dropped soles insufficient 

 seating out of the shoe is also a cause. Irregular and insecure 

 fitting and shifting of the shoe from carelessness in nailing on 

 may also cause strain of laminae in the heel. Bad shoeing 

 usually produces corns of the sole. In certain circumstances 

 stones, becoming fixed between the frog and the heel of the 

 shoe, bruise the sole. 



Inasmuch as dryness is injurious to the hoof it may also 

 produce corns. It renders the horny box hard and unyielding 

 and produces a ' shuffling ' gait at the commencement of work. 

 After long continuance of wet weather the sole may become 

 softened and so rather more liable to bruising, yet this is only 

 of importance when other causes are also acting. 



The very real character of the complaints as to hard roads, 

 fast pace, etc., causing corns is shown by the fact that, in spite 

 of good shoeing, horses which work in towns suffer much more 

 frequently than even badly shod farm horses. 



As shoes cause the entire body-weight to rest on the lower 

 surface of the wall while the sole and frog are more or less 

 suspended (especially when calkins are used), it is not difficult 

 to believe that in the suspciuling parts, ^.c., the sensitive lamiuse, 



