DISEASES OF THE LATERAL CARTILAGES 347 
A better method, however, when the dressing lends itself 
to the purpose, is to use it in the form of a powder, wrapped 
in the form of small cubes in extremely thin paper, such, 
for instance, as is used for rolling cigarettes. It is then 
conveniently inserted into each fistula. Introduced in this 
more finely divided form the drug is, perhaps, a little more 
active in bringing about the desired result. 
This method of ‘ plugging,’ although practised by many, 
we cannot recommend in preference to the use of the hot 
iron or of liquid injections. Our reasons are these: the 
action of the drug is a protracted one. Almost immediately 
after its introduction into the fistula there is formed about it 
an almost impermeable layer of a metallic albuminate, which 
effectively prevents further rapid action of the caustic. In 
addition to thus preventing further action of the dressing, 
this combination of the tissue albumin with the metal of 
the salt, together with much necrotic tissue that it has 
caused, is extremely hard to remove from the healthy tissues. 
This we explain by pointing out that the action of the 
caustic, prolonged as it is, sets up a tissue reaction which 
partakes largely of the type of a chronic rather than an 
acute inflammation. With a chronic inflammation there is 
sooner a tendency to the production of fibrous tissue (and 
thus the firmer attachment of the necrosed portions) rather 
than an active phagocytosis and the casting-off of a slough. 
Again, careful though we may be with the probe, it is 
extremely difficult to be certain that we have discovered the 
whole extent of any fistula. An equal difficulty, therefore, 
exists in being certain that we have placed the caustic in the 
position in which it is most wanted—namely, at the further- 
most end of the fistula where the necrotic tissue is to be found. 
When a caustic is used at all, it is far better to employ it 
in the liquid form, when either of the drugs we have just 
mentioned may again be used. In the first place, the liquid 
is far more likely to be brought into contact with the diseased 
structures than is the solid salt. Also, its action may be 
regulated by altering the strength of the solution, and the 
liability to form impermeable albuminates thus dim‘nished. 
