102 



RHEUMATISM. 



synovial sacs appear distended, fluctuating and in exactly the same 

 condition as in ordinary bog-spavin. This is what has been termed the 

 exudative form of infectious arthritis. In the second, the enlarged joint 

 remains very sensitive, the walls of the synovial sac are thickened, 

 fluctuation is either absent or only slightly marked, but induration is 

 very manifest. This constitutes the plastic form. 



Exudative arthritis is the form usually seen at first. It may preserve 



Fig. 56. — Plastic form of infectious rheumatism (pseudo-anchylosis). 



its primary characteristics, but only too often proves to be the fore- 

 runner of the plastic form, which develops with the lapse of time. If 

 nothing is done wasting becomes more marked, and is accompanied by 

 cachexia. The animals are unable to rise, the complications insepar- 

 able from decubitus occur, and wasting or secondary purulent infection 

 sets in. 



Lesions. In the exudative form the changes are confined to inflam- 



