RHEUIMATOID ARTHRITIS. 



269 



healthy hocks emit at times a simihir creaking suuud, winch, tli(.ic- 

 fore, cannot be regarck'd as peculiai' to this disease ; althniiuli, 

 possibly, it may be a constant symptom. There is always a ceiiain 

 amount of stiffness in the joint, with, at times, marked lameness. 

 In some cases, while the horse was at work, I have seen sadden and 

 most painful lameness occur, even to tlie extent of the animal 

 holding up the affected limb off' tlie ground for a short time. This 

 seizure would pass off" after a few minutes' rest. The cause of it, I 

 presume, was the detachment, from the diseased cartilage or bony 

 deposit, of a particle whicli got lietween the articulating surfaces. 



Fig 101. —rnsition assumed in i-heumaLi>id arthritis of stifle. 



A horse with this disease in the hock may continue capable of 

 a fair amount of work for years. 



(2.) A similar though more acute form of inflammation of the 

 stifle joint. I have met with one case of this in a van (light cart) 

 horse, about nine years old, and which was accustomed to do hard 

 work. Figs. 101 and 102 show the two characteristic positions 

 alternately assumed by him while at rest during the progress of 

 the disease. He would raise the foot off the ground and keep the 

 limb bent for several seconds as in Fig. 101, and then, seemingly 

 because the muscles got tired, would lower the leg down, as in 

 Fig. 102, to be raised again in about half a minute's time. 

 Although the first steps taken were extremely painful, the lame- 

 ness, after that, was not very great. No exciting cause could be 



