346 



the seat of a droi^sical collection a hygroma is formed and the knee is 

 "capped." Though somewhat analogous in its history to the capped 

 elbow, there are points of difference between them. Their development 

 may prove a source of great annoyance from the fact of the blemish 

 which they constitute. 



The capped knee presents itself under various conditions. It is 

 sometimes the result of a cause nearly unique, as when it follows a 

 bruise or contusion, often repeated, inilicted upon himself by a horse 

 addicted to the habit of pawiug while in the stable and striking the 

 front of his stall with his knees. Another class of patients is formed 

 of those weak-kneed animals which are subject to falling and bruising 

 the front of the joint against the ground, the results not being always 

 of the same character. 



The lesion may be a simple bruise, or it may be a severe contusion 

 with swelling, cedematous, hot, painful, and interfering with locomotion, 

 the joint becoming stiff and sometimes so rigid that the animal is unable 

 to Hex it, and still, nnder simple treatment, the trouble may subside 

 almost by spontaneous action. 



Or, again, instead of altogether passing off, the cedema may diminish 

 in extent, becoming more defined in form and remain as a tumor more 

 or less developed on the front part of the knee. Eesulting from the 

 crushing of small blood vessels, this is essentially a bloody tumor. It 

 is somewhat soft, not painful, surrounded by a little swelling, round, 

 more or less fluctuatiug, and after a few days becomes crepitant under 

 the pressure of the hand. 



But instead of possessing all the characteristics of a bloody tumor it 

 may also assume those of a serous growth, as often occurs when the vio- 

 lence (the bruise), though perhaps slight, has been frequently repeated. 

 In that case the tumor becomes better defined, generally painless, with- 

 out any surrounding swelling, is much softer, is iluctuating, and more 

 or less pendulous. 



In other cases, however, this serous tumor becomes the seat of an 

 acute inflammation, perhaps from repetition of the original violence ; or 

 it may set in as the immediate result of the bruise, and a phlegmonous 

 inflammation may thus be established. The tumor is now surrounded 

 with oedema, more or less diffused, and becomes hot and painful. The 

 flexion of the knee can no longer take place ; walking is much inter- 

 fered with— a large acute abscess has been formed, and it is this that 

 constitutes the capped Imee. 



Whatever may be the nature of the tumors, whether shown when 

 opened to be bloody, cystic, or purulent, or when they ulcerate as they 

 sometimes do, though the cavity of the abscess may fill up in a short 

 time, the probability is that there will always remain in front of the 

 knee a plastic deposit, developed in varying degrees, which will resist 

 all treatment and continue unabsorbed for life. 



Though simi)le bruises of the knee without extensive lesions are usu- 



