1 58 CAUTERIES. 



as a benzine reservoir and saturator, carrying at its extremity a 

 small iron box with a conical base, through which is drilled a hole 

 for the passage of the needle. This latter is held on a movable 

 arm, which permits it either to be protruded through the base of 

 the box or to be retracted within the latter by a spring. A bellows 

 and benzole container supply the heat, the flame playing within the 

 cavity of the iron box. Each time a puncture is to be made the 

 red-hot needle is protruded from the point of the box and thrust 

 into the tissues. The action of the spring automatically returns it 

 to the interior of the box, where the flame almost immediately renders 

 it hot again. 



The two following firing instruments were described by the writer 

 some years ago (see " Veterinarian," February, 1898). They have 

 been used by him in his practice for many years, and both have been 

 found very satisfactory. The first is Graillot's Zoo-cautery (Fig. 215). 



It is an adaptation of Paquelin's, which depends for its action 

 on the peculiar property possessed by metallic platinum, and in an 

 even higher degree by platinum in a finely divided state (platinum- 

 black), of bringing about chemical combination between oxygen 

 and hydrogen gases, or between oxygen and certain hydrocarbon 

 vapours, without the intervention of a flame. The zoo-cautery 

 consists, as shown by the annexed rough sketch, of three principal 

 parts, viz. the handle, forming a benzoline reservoir, the stem, and 

 the head. 



The handle (b) is formed of thin metal, spun on a lathe and 

 corrugated, both to afford a better grip and to increase the surface 

 from which evaporation takes place. Its interior is packed with 

 fragments of sponge saturated with benzoline, and through the centre 

 passes a small tube, which conveys a portion of the air, pumped 

 into the apparatus directly towards the stem, without passing through 

 the sponge. At the extreme end of the handle is a nipple, over which 

 is slipped the india-rubber tube of the bellows, and a little two-way 

 stopcock (a), which when turned in a line with the handle allows air 

 to pass freely both through the small (direct) tube mentioned, and 

 also through the mass of sponge in- the handle ; but when turned 

 at an angle gradually shuts off the stream from the sponge-packed 

 part until at last (at right angles) it admits air alone through the 

 direct tube. By examining the top of the handle before screwing 

 in the stem the small direct air-tube will be seen projecting upwards 

 through the mass of sponge. 



The stem (c) is merely a strong metallic tube supporting the head, 

 and conveying to it the mixed air and benzoline vapour delivered 



