248 KNEE JOINT LAMIi^NESS. 



with the sound leg, but which very quickness causes a shortening 

 of the step : the effect of this is to give a horse a tendency to go 

 round in a large circle, evinced by the horse bearing to the sound 

 side; and so early does this occasionally shew itself, that it will be 

 often the first intimation of the existence of lameness. 



"There is a tendency to drop the fore quarters, but not to the 

 same extent as where both joints are affected. 



"The characters are very much akin to those considered to be- 

 long to shoulder lameness, but from which it may be readily distin- 

 guished ; first, by the circumductive manner in which the leg is 

 thrown forwards, and the straight knee ; secondly, by the absence 

 of the dragging or striking of the toe against the ground ; thirdly, 

 by the stepping on the heels and the greater firmness on standing; 

 but, perhaps, one of the best guides in diagnosis is noting which- 

 ever joint is attempted to be least brought into use. 



" I have sufficiently pointed out the distinction between carpitis 

 and navicularthritis ; but there is one fact which I cannot clearly 

 account for, that is the heat of the foot of the lame limb in carpitis: 

 this at first I found a very considerable obstacle in diagnosis; but 

 I have noticed its presence in so many instances, that all doubt 

 respecting its existence has ceased. 



" There are, however, instances in which I have noticed its 

 absence : whether this depends upon a particular part of the car- 

 pus being affected, I am not prepared to say, though I believe 

 such to be the case. I suppose it to arise from a similar cause to 

 that which produces in man pain in the knee joint from disease of 

 the hip, from pressure applied to or irritation affecting the trunk 

 of the nerve, and which is referred to its extremities. 



"The Horses most likely to be the Subjects of this 

 Disease are those with straight upright legs and short pasterns, 

 because in those the weight is thrown directly upon the bony 

 column ; and I have noticed that horses with legs of this descrip- 

 tion have generally but small knee joints. 



'' I am disposed to entertain a belief that there is in some 

 horses an hereditary idiosyncrasy to this disease ; be this as it 

 may, half-bred are much more prone to it than thorough-bred 

 horses. 



