332 VETERINARY SURGICAL THERAPEUTICS. 
into the cavity. A trocar, 2 or 3 millimeters in diameter, will be used, its. 
three-faced point will penetrate through the tissues and leave an imper- 
ceptible opening which closes at once. Leblanc operated with the animal 
standing, but it is better to 
cast him. The leg to be. 
operated on is carried in 
extension. After all aseptic. 
precautions have. been taken 
(see Antisepsy), the operator 
takes hold of the trocar with 
the right hand, limiting his. 
entrance through the tissues. 
with his fingers, and he pushes. 
it perpendicularly to the skin, 
or in a slight oblique direc-. 
tion, by a gradual pressure 
with some rotatory motion. 
The rod removed, a jet of 
synovia escapes more or less. 
abundant, according to the 
tense condition of the sac; 
sometimes, however, it is nec— 
essary to squeeze the tumor 
to accelerate the flow. At 
the clinic of Alfort we use. 
generally the aspirator of 
Dieulafoy or that of Potain 
(figs. 79 and 80). Must the 
synovial be entirely emptied > 
Barry recommended to ex-- 
tract only a small quantity ;. 
he wished to reduce the effects of the iodine by mixing with the synovia ;. 
! there is, however, cases where this is grumelous and escapes with difficulty ;: 
‘and only a portion of it is removed ; but when it flows freely, as much as: 
possible must be extracted. It is not necessary to inject a large quantity 
of the iodine; according to the size of the sac, from 20 to 100 grammes. 
are sufficient. An ordinary syringe can be used, though special instruments. 
are better. The fluid is left in the pouch for a few minutes only; gentle- 
pressure insures the intimate contact of the irritating fluid with every 
point of the diseased membrane ; then a second evacuation is to be made. 
This is sometimes difficult, even with the aspirator; clots filling up the 
canula of the trocar. Sometimes the greater quantity of the fluid has to 
Fig. 79.—Dieulafoy’s Aspirator. 
