122 
FRED. SAUNDERS. 
constant displacement and replacement was repeated several 
times, until the following day, when it became first difficult, then 
impossible, to reduce it. Hot fomentations and chloroform lini¬ 
ment were then prescribed ; it was, however, impossible to return 
• 
the bone to its place. 
On the 5th of May a severe blister was applied over the stifle, 
extending well around the joint, and embracing, as much as pos¬ 
sible, its whole surface, and even beyond it. For twenty-four 
hours the leg maintained its condition, extended backwards as 
soon as the slightest motion forward was attempted. On the fol¬ 
lowing morning, the bone, which had once returned to its posi¬ 
tion, was found again out of place. The parts were swollen, and 
thick exudation had taken place. The animal was left alone, 
and during the day was found using his leg as well as ever, with 
the exception of the slight inconvenience that the blister occa¬ 
sioned. 
On the 13th of May the blister was washed off, and the animal 
turned loose in a box stall. He, however, showed considerable 
lameness; and, though the scabs of the blister were almost all 
gone, and the swelling had disappeared, when walked, he would 
move with a lame step, slightly dragging his toe. 
He was discharged on the 18th. 
The object of the report is to add a point to the history of 
the true dislocations of . the patella, and to show its difference 
from the pseudo-dislocation, as the result of excessive muscular 
contraction of the anterior crural region. In this case, the his¬ 
tory of a previous similar attack, the difficulty of permanent re¬ 
duction, the resistance to treatment first, the lameness persisting 
nearly three weeks afterwards, seem to me an evidence of true 
dislocation, as these symptoms and conditions would not have 
been present had the difficulty been only mechanical; that is, the 
catch of the patella over the superior segment of the internal 
border of the femoral notch, as described by M. Chuchu in his 
discussion before the Central Society of Veterinary Medicine of 
Paris. 
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