INTRODUCTION 
XXXV 
the fibres of the cloth. This antiseptic gauze had carbolic acid thus fixed in every 
fibre, while the fine spaces between, which give its porous character to the cloth. 
were still open for the discharge to pass through. It was folded in such a way 
as to make a thickness of eight plies and placed over the wound, overlapping it 
widely in all directions. But in order to prevent fluids from solng straight 
through the eight plies of gauze and possibly exhausting its antiseptic ingredients 
at that part, a piece of very thin macintosh or jaconet, previously washed in the 
antiseptic lotion, was incorporated with the mass of gauze by being slipped 
under its top layer, thus leaving seven layers of the gauze next the wound, and 
compelling the discharges to make their way to the margins of the dressing, 
instead of coming straight through. 
As has already been said, the whole aim of Lister’s work was to bring about 
and maintain in an open wound conditions similar to those which exist in a 
subcutaneous injury, and from the first he fully recognised that while fermentative 
changes were the most important they were not the only sources of irritation— 
that in fact the chemical substance employed to prevent fermentation was also 
more or less irritating, and interfered with the attainment of his ideal. He there- 
fore now directed his attention to devising means of diminishing or altogether 
avoiding irritation of the wound by the carbolic acid contained in the dressings. 
The irritation produced by the antiseptic which came into contact with the wound 
during the operation was only temporary. The carbolic acid when mixed with 
the blood lost much of its irritating character, and was moreover absorbed, 
and disappeared from the wound in a comparatively short time. When once 
the wound had been closed at the operation, Lister considered it unnecessary 
to irritate the line of incision or the interior of the wound by subsequent appli- 
cations of the antiseptic. He therefore never syringed out a wound at a subse- 
quent dressing, as some surgeons were fond of doing; the utmost he did was to 
have some carbolic lotion flowing over the line of incision and the adjacent skin 
while the dressings were being changed. This lotion did not penetrate into the 
interior of the wound, and acted on the surface only for the brief period during 
which it was exposed. Nevertheless he recognised that the carbolic-acid vapour 
coming off from the gauze or the lac-plaster was irritating to the line of incision, 
and therefore he made numerous experiments with the view of finding some 
material more or less impenetrable to the vapour of carbolic acid, which might 
be placed directly over the wound below the carbolic gauze, but widely ove! 
lapped by the absorbent antiseptic gauze dressing. Though the vapour o! 
carbolic acid passed easily through gutta-percha tissue and thin sheets o! india- 
rubber, the common oil-silk used for covering water dressings was found to b 
much less penetrable by it. Taking this as a basis, he covered it with 
Cc ? 
