214 DISEASES OF THE FEET. 



new growth. The tumour, which is usually slow in its course, 

 may be accompanied by the formation of pus, which, by reaching 

 the coronet, may give rise to a quittor. Mr. Wild M.R.C.V.S. 

 ("Veterinarian," January, 1894) describes a horn tumour which 

 he extracted from a horse's foot, as a piece of dark-coloured horn 

 somewhat resembling a horse's incisor tooth, with the crown point- 

 ing downwards, and weighing about three drachms. It is in- 

 structive to note that the development of the teeth closely re- 

 sembles that of horn, hair and cuticle (scarf-skin or outer skin) ; 

 all being forms of epidermal growth (p. 154). 



The CAUSE is generally injury, as for instance " tread " when 

 the growth has begun at the coronet ; or the act of hammering down 

 clinches of the nails or clips of a shoe; or puncture of, or pressure 

 on the sensitive laminae by an ill-directed nail. 



The usual SYMPTOMS are : lameness, which may come on very 

 gradually; pain on tapping the part; and local lieat. Signol 

 (" Aide-memoir du Veterinaire ") remarks that the lameness of a 

 horn tumour at the toe is similar to that of chronic laminitis. I 

 have observed in a horse I treated, the fact remarked on by 

 Moller that if the tumour begins at the coronet, it will usually 

 cause the horn of the wall which covers it to bulge outwards. 



TREATMENT.— Cut down on the tumour from the outside of 

 the wall of the hoof; poultice the part for two or three days; 

 remove the tumour with a pair of pincers, aiding the operation 

 with the knife ; and treat the wound a-ntiseptically (p. 69). If 

 the bone be affected, it may have to be scraped to remove any 

 dead parts. The cavity may be dressed like that of seedy-toe 

 (p. 202). Moller states that the disease is very liable to recur. 



Wounds and Bruises of the Coronet. 



These injuries generally appear in the form of " tread," which 

 is the term applied to a wound inflicted upon the coronet of one 

 foot by the other fore or hind foot, as the case may be. The 

 usual causes of tread are : weakness ; fatigue ; over-taxation of 

 strength ; and carelessness in turning the animal, especially when 

 he is in heavy draught, and when he has been shod with "roughed 

 shoes." Tread is principally confined to cart-horses. The more 

 forward is the injury to the coronet, the greater will be the 

 danger of hurting the extensor tendon of the foot and the joint 

 formed by the pedal bone and the short pastern bone. We may 

 note that the extensor tendon of the foot runs down the front 

 of the pastern and is inserted on the upper and front portion 

 (pyramidal process) of the pedal bone (Figs. 5, 7 and 70). 



