CHRONIC VILLITIS 



383 



They require the services of the most enlightened and painstaking prac- 

 titioner, who will recognize the changes for good or ill as they occur, and 

 will regulate his treatment accordingly. 



CHRONIC VILLITIS 



Beneath the hoof -horn extending round the coronet is a prominent 

 band of fibrous tissue called the coronary cushion. Its surface is covered 

 with a large number of closely -packed vascular villi little projecting 

 bodies which have been likened to the pile on velvet (fig. 400). 



Each of these little processes fits into a small hole in the coronary 

 groove of the hoof, and from them 

 the crust is produced and reno- 

 vated. This being the case, it is 

 most important to the integrity 

 and strength of the crust that the 

 coronary cushion should be in a 

 healthy condition; and so long as 

 it is so, the horn which it forms is 

 ample in quantity, and possesses 

 the normal hardness, toughness, 

 density, and thickness. When, 

 however, inflammatory disease 

 affects the secreting villi and the 

 fibrous cushion, from which they 

 proceed, the horn becomes altered 

 in quality, and, losing the cohesive 



property by which its fibres are bound together, it becomes dry, loose 

 in texture, and crumbles away. This changed condition is due to two 

 factors (l) the altered nature of the horn secreted; (2) the separation 

 of the secreting villi from one another by the swelling and expansion 

 of the coronary cushion, whereby the horn fibres are made to stand 

 apart from each other, and fail to form that close compact mass of horn 

 which the crust presents in a healthy condition. 



Causes. Some horses inherit a dry and brittle state of the hoof-horn, 

 and are specially liable to chronic villitis. Blows to the coronet are the 

 chief exciting causes, and the writer has also seen it follow upon a severe 

 blistering, quittor, and sand crack. 



Symptoms. Chronic villitis most frequently affects the front region 

 of the coronet. Sometimes it attacks but a small surface, at others it 

 extends for some distance towards the quarters. It commences by swelling, 



Fig. 400. Villi ot the Coronary Cushion and 

 Growth of Horn 



a, Villi of the Coronary Cushion. I, b, Horn of the hoof, 

 with tubes in transverse section, c, Vessels of the villi. 



