INJUKIES TO INFLAMMATION OF CORONET. 387 



tree (fig. 363). Above the perioplic ring the epidermis usually 

 shows an abundant growth of bran-like scales and crusts (as in 

 dry eczema). In many cases the perioplic ring appears denuded 

 of horn and so swollen as to project considerably above the 

 upper margin of the wall. The disease takes a chronic course. 

 The causes are only partially understood. The perioplic 

 ring, especially in pigmented hoofs, appears covered with dry, 

 rough, brittle scales. Where fragments have broken away the 



FiQ. 363. — Showing appearance of hoof after long-coutinued inflammation of 



the perioplic ring. 



reddened and inflamed perioplic ring becomes visible. Treads 

 on the coronet or the use of irritants (frequent poulticing, 

 grease, etc., etc.) may give rise to this condition. Gutenacker 

 describes cases caused by the use of unrefined vaseline. 



Treatment consists principally in removing the cause. The 

 parts are thoroughly cleansed with water and (carbolic) soap 

 and any proliferations or thickenings removed. Gentle infric- 

 tion with boric acid ointment or 3 per cent, carbolic ointment 

 has been followed by good results. Some recommend sulphur 

 ointment, consisting of sulphur 2 parts, lard or lanoline 5 parts, 

 or a lotion of 2 parts tartaric acid in 100 parts glycerine, with 

 the addition of 3 to 5 parts creolin. * When deep cracks form 

 and discharge, a pressure bandage combined with astringents 

 is often useful. 



5. Corns. 



In the widest acceptance of the word a corn may be defined 

 as a bruise sustained by the keratogenous membrane. Corns 

 are recognised by the yellowish-red or purple colour of the 



