DISEASES OF THE JOINTS 419 
a prick, the pus formed may in many instances be very 
near the capsular ligament of the articulation. Under 
such circumstances, unless there is a free and unhindered 
flow of the pus from an outside opening, inroads will be 
made by it upon the thin capsule. The latter is quickly 
penetrated, and pus is admitted to the interior of the joint. 
In other cases infection of the joint may proceed from 
within, from a poisoned state of the blood-stream. The 
condition occurs, for instance, in bad attacks of laminitis. 
We ourselves, too, have seen two cases where suppuration 
of the pedal articulation occurred in the septic pyemia of 
foals, a disease known commonly as ‘ joint-ill,’ and charac- 
terized by an infected state of the circulation. Cases have 
also come under our notice where this condition has resulted 
from slight injuries in the region of the insertion of the 
extensor pedis inflicted by the animal himself when galloping 
away. 
Perhaps, however, the most common cause of suppurative 
arthritis in the foot is direct penetration of the articulation 
in the case of pricks. The penetrating object is nearly 
always dirty—bacterially dirty, at any rate—and sup- 
puration only too readily commences. Even should such 
a wound be inflicted by an aseptic body, infection would 
quickly ensue as a result of the wound gathering dirt from 
the ground, or even from admission to the joint of impure 
and bacilli-laden air. 
Symptoms and Diagnosis.—This is one of the most serious 
conditions we are called upon to face when dealing with 
diseases of the foot, for in many cases it quickly ends in 
exhaustion and death of the patient, while in even the 
most favourable cases nothing better than a condition of 
complete and bony anchylosis is to be expected. The owner, 
therefore, should be warned accordingly. 
As in the other joint affections, so here, we get all the 
symptoms of acute febrile constitutional disturbance. The 
pulse, the temperature, the respirations, and the general 
haggard, ‘ tucked-up,’ and distressed appearances of the 
animal all tell too plain a tale. Our patient is in constant 
pain, and the seat of the trouble is clearly enough shown 
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