390 INFLAMMATION OF STRUCTUEES ENCLOSED BY THE HOOF. 



horn is greatly discoloured, permeated with cracks, blood- 

 stained, and of soft consistence. 



Long continued irritation of the sensitive wall produces 

 change in the horn of the quarters and heels. The sensitive 

 wall often loses its laminated character .at the centre of 

 suppuration and exhibits a deep groove devoid of laminae, 

 though without sacrificing its power of producing horn. 

 Though no horny laminae are produced, the space becomes 





-w^,' 





m 





Fig. 366.— Portion of the inner surface of 

 the wall showing changes after old 

 standing corn, a, horn tumour. 



111- !?',■.••■:■. 'A" ■'■) w 



Fig. 367. — Ground surface of pedal bone 

 showing bony enlargements on the wings 

 (retrossal processes) in consequence of old 

 standing corn. 



filled with horn, which forms firm masses or tumours of vary- 

 ing size (fig. 365, c, and 366, a). The wings of the os pedis 

 become enlarged, in consequence of chronic inflammation, 

 ostitis or periostitis (fig. 367), as sometimes discovered after 

 death. 



The symptoms of corn are those of inflammation of the 

 corium. In horses visibly lame there is always pain and in- 

 creased warmth. The reddened spot in the heel is found on 

 cutting out the foot. Corns may be due to very varied causes, 

 and are by no means consequent on bad shoeing alone. Such 

 causes are often to be found in the formation of the hoof 

 itself or even in the conformation of the limb. Hence certain 

 animals suffer more frequently than others, in spite of the 

 best attention in shoeing, while, in consequence of the greater 

 load thrown on them, the fore are much more liable to corns 

 than the hind feet. 



Unequal distribution of weight in feet which are turned in 

 or out largely influences the position of the corn, which is 



