sand-cracks. Fast work on hard roads, jumping, and blows on the 

 coronet, together with calk wounds of the feet, are accidental causes 

 of quarter-cracks in particular. Toe-cracks are more likely to be 

 caused by heavy pulling on slippery roads and pavements or on 

 steep hills. 



Symptoms. The fissure in the horn is ofttimes the only evi- 

 dence of the disease ; and even this may be accidentally or purposely 

 hidden from casual view by mud, ointments, tar, wax, putty, gutta- 

 percha, or by the long hairs of the coronet. 



Sand-cracks sometimes commence on the internal face of the 

 wall, involving its whole thickness excepting a thin layer on the 

 outer surface. In these cases the existence of the injury may be 

 suspected from a slight depression, which begins near the coronary 

 band and follows the direction of the horny fibers; but the trouble 

 can only be positively diagnosed by paring away the outside layers 

 of horn until the fissure is exposed. In toe-cracks the walls of the 

 fissure are in close apposition when the foot receives the weight of 

 the body, but when the foot is raised from the ground the fissure 

 opens. In quarter-crack the opposite is true ; the fissure closes when 

 the weight is removed from the foot. As a rule, sand-cracks begin 

 at the coronary band, and as they become older they not only extend 

 downward, but they also grow deeper. In old cases, particularly in 

 toe-crack, the horn on the borders of the fissure loses its vitality and 

 scales off, sometimes through the greater part of its thickness, leav- 

 ing behind a rough and irregular channel extending from the cor- 

 onet to the end of the toe. 



In many cases of quarter-crack, and in some cases of toe-crack 

 as well, if the edges remain close together, with but little motion, the 

 fissure is dry; but in other cases a thin, offensive discharge issues 

 from the crack and the ulcerated soft tissues, or a funguslike growth 

 protrudes from the narrow opening. When the cracks are deep, and 

 the motion of their edges considerable, so that the soft tissues are 

 bruised and pinched with every movement, a constant inflammation 

 of the parts is maintained and the lameness is severe. 



Ordinarily the lameness of sand-crack is slight when the patient 

 walks ; but it is greatly aggravated when iie is made to trot, and the 

 harder the road the worse he limps. Furthermore, the lameness is 

 greater going down hill than up, for the reason that these conditions 

 are favorable to an increased motion in the edges of the fissure. 

 Lastly, more or less hemorrhage accompanies the inception of a sand- 

 crack when the whole thickness of the wall is involved. Subsequent 

 hemorrhages may also take place from fast work, jumping, or a mis- 

 step. 



Treatment. In so far as preventive measures are concerned, 

 but little can be done. The suppleness of the horn is to be main- 

 tained by the use of ointments, damp floor, bedding, etc. The shoe is 

 to be proportioned to the w r eight and work of the animal ; the nails 

 holding it in place are to be of proper size, and not driven too near 

 the heels ; sufficient calks and toe-pieces must be added to the shoes 



