ORGANS OF LOCOMOTION 231 



be disposed of several days after the cessation of the symptoms of 

 an attack. 



POLYARTHRITIS 



Polyarthritis is a name applied to a condition in which there is 

 involvement of various joints of the legs. This condition has been 

 quite prevalent in some sections of the country. The number of 

 cases observed varies during different years. The disease is of eco- 

 nomic importance because it results in unthriftiness and therefore 

 the affected animals do not develop and fatten normally. The dis- 

 ease does not appear to be confined to any particular type or breed 

 of swine and occurs equally in males and females. 



Etiology. — It has been stated, although never positively proved, 

 that confining pigs on cement floors or cold damp quarters is an 

 important predisposing factor. According to the findings in abat- 

 toirs, there are proportionately more cases after severe winters or 

 cold springs than after mild winters. The B. pyogenes has been 

 claimed to be the specific cause of polyarthritis. It may be that this 

 disease is a chronic condition resulting from navel infection. 



Lesions. — The lesions are variable depending upon the intensity 

 and chronicity of the processes. There may be a mild inflamma- 

 tion of the synovial membranes with limited or extensive infiltration 

 and tumefaction of the perisynovial structures. In the early stages 

 the synovial membrane is congested, and as the disease progresses 

 varying quantities of fiuid accumulate in the joint cavity. The 

 accumulated fiuid will be turbid and may contain coagulated mate- 

 rial. In the later stages of the more chronic cases there will be a 

 a thickening of the synovial membrane due to fibrous proliferation. 

 Fibrous formation may involve consideration of the perisynovial 

 structures and be sufficiently dense to render the joint immobile or 

 nearly so. The articular cartilages may be eroded and there may 

 be organization and fibrous proliferation within the joint cavity, 

 thus rendering movement impossible. The affected animals are not 

 fully developed and in the more severe cases are not in good flesh. 



Symptoms. — In the beginning the affected animals show locomo- 

 tory disturbances and the joints are swollen and sensitive. When 

 the disease has assumed the chronic form the affected animals appear 

 unthrifty and there may or may not be visible enlargement of the 

 joints. There will be interference with joint action. 



Treatment.— Pretention offers the only solution of overcoming the 



