* 
80. VETERINARY SURGICAL THERAPEUTICS. 
cauterizing edge must be slightly convex, blunt throughout its: 
whole extent, rounded at its angles; and its rod would better be 
moderately rounded in. With such instruments the uneven parts. _ 
of the region can be well followed, and the heat evenly distributed. 
The active part of point cautery (fig. 37) is disposed in a conicalform.... 
more or less elongated ; it~ 
varies in size. For penetrat- 
ing or deep pointed firing, a. 
cautery more elongated than 
the preceding is used. Abadie’ 
has recommended an instru- 
ment with which he could. 
run through the subcutaneous 
connective tissue and deep 
into the tissues. When one 
does not wish to go beyond. 
the subcutaneous connective - 
tissue, ordinary  cauteries 
more or less elongated an-. 
swer all purposes. Meedle' 
Cauterization requires very fine 
needles which can penetrate. 
all tissues. At first iron need- 
les, 2 millimeters in diameter, 
Fig, 37—Lines firing iron, Dots firing iron, and one or two decimeters . 
Sharp pointed firing iron, long, were used ; heated to 
red heat, they were taken 
hold of with nippers and implanted in the tissues. Bianchi, Lenck, 
Foucher, have recommended cauteries having an olivary part, 
terminated by a point of iron or platinum. The most of those in- 
struments with a separate needle cool off too quickly and burn the 
skin round the perforation. To protect the skin, Watrin had a 
little disk of metal placed between the needle and the olivary part 
of the cautery. 
Bourguet (fig. 38), Vasselin, Hermann, and Ehret have invented the 
first cauteries with movable needles and independent heating. 
That of Bourguet is superior to all others, and we use it often at 
Alfort, with best results. A screw (A) regulates the penetration of 
the needle, which is heated in the interior of the heat carrier, a 
slight pressure from downwards upwards upon the branch F pushes 
it out; as soon as it is removed from the tissues, it is allowed to 
return to the heating mass, which is fixed by a spring (M). A 
screen protects the skin. Notwithstanding its apparent complexity, 
this instrument is remarkable for its solidity and the regularity of its 
working. 
