244 MICROBES, FERMENTS, AND MOULDS. 
be their origin, and should be renewed whenever the 
wound is dressed. 
We-cannot describe Lister's dressing in detail, but 
will only mention—(1) that the skin surrounding the’ 
region of the operation, the surgeon’s hands, and the 
instruments are washed with a carbolic solution of two 
to three per cent. ; (2) the spray contains one per cent, 
of carbolic acid ; (3) the ligature of the arteries is done 
with carbolized catgut, which is eventually dissolved 
in the wound; (4) the drainage-tube usually arranged 
for the outflow of the discharge is likewise carbolized ; 
(5) so also are the eight folds of gauze, which is 
used instead of linen dressings; (6) a protective, con- 
sisting of green oiled silk, steeped in carbolic acid 
and varnished like court-plaister, is interposed to 
prevent the irritating effect of the gauze on the 
wound; (7) animpermeable mackintosh, laid between 
the seventh and eighth folds of gauze, prevents the 
penetration of fluids. 
The admirable results obtained by Lister’s method 
are the strongest confirmation of the truth of the 
theory of microbes. Since its introduction into 
medical practice, mortality among the wounded and 
among thesurgical patients has considerably diminished, 
and operations formerly considered impracticable have 
been undertaken and successfully carried out. 
Carbolic acid is not the only antiseptic which 
affords excellent results by destroying, or at all events 
by attenuating, the virulence of microbes and their 
