196 THE HORSE IN HEALTH AND DISEASE 



bath. Give saltpeter in 2- to 4-ounce doses in the drinking-water 

 three times daily, and if at all costive a quart of raw linseed oil. 

 The grain ration should be materially cut down. 



Chronic laminitis develops from the acute form. The coffin- 

 bone rotates and presses on the upper surface of the sole, which in 

 turn gives under the pressure and a "dropped sole" results. These 

 changes lead to the formation of prominent rings and a concave 

 instead of a straight toe wall. When standing the horse shifts his 

 weight from one foot to the other; when traveling, the gait is stiff 

 and the steps short and choppy. This peculiarity has led horsemen 

 to believe that the soreness is in the chest, the pectoral muscles 

 of which atrophy, and has given rise to the misnomer "chest 

 founder." 



Permanent rehef cannot be expected from any line of treatment. 

 However, by keeping the toe rasped down and applying a rubber 

 heel pad or bar shoe a badly affected animal may be kept from 

 getting severely lame, and should give good service on soft roads 

 or ground. Hoof-packings and dressings' to supply and conserve 

 the moisture of the foot often afford material help. 



SIDEBONE 



A sidebone occurs when one of the lateral cartilages attached 

 to the wing of the third phalanx or coffin-bone ossifies (Fig. 60). 

 There are various causes of which a hereditary predisposition to 

 lime-salt deposition in cartilaginous tissue appears to be the most 

 common. Horses with flat feet and weak quarters are also pre- 

 disposed to this disease. It is quite as certain that injuries from 

 treads and similar wounds also set up an inflammation about these 

 structures that may later result in sidebone formation. Lameness 

 may or may not be present. In the later stages of the disease the 

 only symptom is the hard, unelastic prominence just above the 

 coronary band. It may be either unilateral or bilateral, and occur 

 on any foot, but is more frequent in the front feet than the hind. 

 In many cases only the lower portion of the cartilage undergoes 

 ossification, the rest retaining its normal elasticity. Blistering or 

 firing aggravates rather than remedies a sidebone. The most satis- 

 factory treatment is to take the horse off city pavements and put 

 him at work on soft ground. As a last resort, after other means 

 have failed, unnerving may be attempted. Sidebones are properly 

 classed with the unsoundnesses, although they do not interfere 



