8 ANTISEPTIC TREATMENT OF WOUNDS. 
And now we are ready to proceed with the operation. The 
same is carried through under a steady spray, even as far as the 
bandage is concerned. As the haemorrhage must be 
arrested or controlled, the ligatures must also be aseptic. 
LISTER introduced a material for that purpose which is also 
used at present and which has the advantage of becoming ab- 
sorbed, namely, the catgut. This was made aseptic by being 
soaked for two months in an emulsion of one part of carbolic 
acid and. five parts of olive oil, and was used both for ligating 
vessels as well as suturing. In the latter case LISTER substi- 
tuted the catgut with carbolized silk, especially if the sutures 
had to stand a stronger strain. After inserting carbolized rub- 
ber tubes in the wound for drainage, LISTER put on the 
bandage, which, according to his idea, would save the wound 
from external infection. At this time he recommended wad- 
ding as bandaging material, on account of its property of 
keeping back the putrefactive germs of the air, but he did not 
follow this theory, as it was not reliable enough for him (we 
will see later that he did injustice to the wadding), and he 
therefore substituted gauze saturated with carbolic acid. The 
bandage was formed thus: On the wound itself came a piece 
of protective silk, then eight layers of gauze; between the sev- 
enth and eighth layers a piece of mackintosh was placed, and 
the whole thing fastened with several turns of gauze bandage. 
The idea of the protective silk in the bandage was to prevent 
the irritation caused by the wound coming in direct contact 
with the carbolic acid through the gauze. The secretions of 
the wound were to be absorbed by the carbolized gauze, but to 
prevent their passing through the eight layers and exposing 
them to infection by the air, the piece of mackintosh was in- 
serted. 
In this manner LISTER treated fresh wounds, but in wounds 
which were of longer standing, therefore already infected, he 
acknowledged that the above mentioned methods were not suf- 
ficient, being fully aware of the fact, that for the removal of 
sepsis, if present, stronger carbolic acid solutions were needed 
than for preventing infection of a fresh wound. On this ac- 
