270 ■ DISEASES OF CATTLE. 



of the joints, and, second, from within through the minute branches 

 of blood vessels which pass into the bones through holes (foramen) 

 on their surface and are distributed in the soft stinicture (medulla) 

 of the inside. The structure of the bone is divided into two parts — 

 the compact or hard material of the outside, which gives strength 

 and is more abundant in the shafts of long bones, and the cancellated 

 softer tissue of the inside, which affords accommodation to the blood 

 vessels necessary for the nourishment of that part of the structure. 



In shape bones are divided into three classes — long, flat, and short. 

 The long bones are the ribs and those mostly found in the limbs ; the 

 flat bones are found in the head, the shoulder, and the pelvis ; and the 

 short bones in the spinal column and in the lower portions of the 

 limbs. 



With this little introduction, which seems almost indispensable, we 

 will proceed at once to the consideration of diseases of bones, for they 

 undergo diseased processes like any other living tissue. 



OSTEITIS. 



Inflammation of the compact structure of bones (osteitis) may be 

 either acute or chronic, and may involve the whole extent of the bone 

 affected or may be confined to only a portion of it. This inflamma- 

 tion results from injury, such as concussion, laceration, or a crushing 

 bruise; also from specific influences, as in actinomycosis or cases of 

 foul foot. The latter affection frequently involves the bones, and for 

 this reason the pastern is the most frequent seat of osteitis. There 

 is dull pain on pressure and a painful swelling of bone when pus is 

 present. Suppuration may involve the overlying soft tissues, causing 

 an abscess, which may finally break through the skin. The inflam- 

 matory condition sometimes assumes an ulcerated form (caries) or 

 from interrupted nutrition of the part deprived of the blood neces- 

 sary to its nourishment may cause death of a large section of bone 

 (necrosis), and this dead fragment (sequestrum)^ becoming separated 

 from the main portion of bone, acts as a foreign body. 



Treatrrhent. — This consists in resting the affected part and in giving 

 vent at the earliest possible moment to whatever pus may be present. 

 Free drainage should then be maintained. Apply dressings of lactic 

 acid or inject with 5 per cent zinc chlorid solution and pack with 

 tampons of cotton soaked in antiseptic solutions. A laxative to keep 

 the bowels moving freely is the only internal treatment necessary. 



PERIOSTITIS. 



This disease is an inflammation of the external covering of bone 

 (periosteum) and is usually produced by wounds, pressure, or crush- 

 ing the part. The periosteum is well supplied with sensitive nerve 



