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) an impermeable 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 the surgical 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 



