DISEASE PRODUCING MALFORMATION OF JOINTS. 275 



part to another. As a rule, if the animal is kept in a warm place, 

 the disease abates in severity in a few days. When the disease 

 takes a chronic form, either from the onset, or merges into the 

 chronic from the acute stage, it resembles very much chronic sero- 

 synovitis. There is great thickening of the capsule, a formation 

 of adhesions between the surface of the joints and the connective 

 tissue, and in rare instances we may have ankylosis of the joint. 

 The most common seat of this disease is in the knee-joint, and still 

 more rarely in the ankle and hip. While the diagnosis is rather 

 diflScult where the disease in confined to one joint, it is easily dis- 

 tinguished when you see it appear in several joints at once, and 

 also from the fact that it may move from one joint to another. 



Disease Producing Malformation of the Joints. 

 (Arthritis Deformans.) 



The cause of this disease is very little known. It is very prob- 

 ably due to a chronic rheumatism, or to some inflammation of 

 the joint. It may also be due to great exertion, and is especially 

 seen in Holland, where animals are used to pull carts and vehicles. 

 The first symptom of this disease is a slight lameness in the dis- 

 eased joint. This lameness may be overlooked, as it is generally 

 very slight, and after the animal has taken a little exercise it grad- 

 ually disappears, although in some rare cases the lameness may 

 continue, or even with exercise become aggravated. In the early 

 stages of the disease there is no indication of pain on movement or 

 pressure of the joint, but later on pain on pressure and motion begins 

 to show itself. At the same time there are a gradual swelling and 

 thickening of the capsule of the joint, with apparently a loss of 

 the normal amount of synovia. Sometimes we notice slight heat. 

 A peculiar symptom of this disease, which is noticed from the very 

 onset, is a peculiar creaking or crepitating sound when the joint is 

 moved. After a time stiffness of the joints becomes more marked. 

 There are hard swellings on the cartilaginous borders, also a ten- 

 dency of the ends of the joint to enlarge, and finally marked alter- 

 ation in the form of the joint. By these changes we are enabled 

 to distinguish between arthritis deformans and chronic serous 

 inflammation of the joints. 



The anatomical alterations have already been mentioned. Arth- 



