176 THE ADDRESS IN SURGERY DELIVERED BEFORE 



The other class of facts in this division of the subject to which I am anxious 

 to direct your special attention was also suggested by one of Tyndall's experi- 

 ments with the condensed luminous beam — that, namely, in which he proved 

 the perfect manner in which cotton-wool filters the air of its suspended particles, 

 by blowing against the beam with a pair of bellows having a mass of the cotton 

 tied over the nozzle ; the result being that the beam, elsewhere white from 

 illuminated dust, became perfectly black at the part on which the current was 

 directed through the cotton-filter : hence the idea naturally suggested itself 

 that cotton-wool might be used with advantage as an antiseptic dressing.^ 

 Of course it would be useless to apply ordinary cotton without special pre- 

 cautions, for, according to the germ theory, putrefactive particles must exist 

 among the fibres and lie scattered over the wool. But if the cotton were 

 impregnated with some volatile material capable of destroying the vitality 

 of the septic organisms, and then placed upon the wound after washing it with 

 a lotion containing the same substance in solution, the result ought to be, 

 supposing the theory true, that, after the volatile antiseptic had become dissi- 

 pated by diffusion from the dressing and from the wound, the cotton-wool, 

 though destitute of any chemically antiseptic properties, should effectually 

 prevent, by its filtering property, the access of any putrefactive agents, and 

 keep the wound sweet, while in itself a perfectly bland and unstimulating 

 application. Accordingly I prepared four samples of cotton-wool by diffusing 

 through each one of the following substances — chlorine gas, sulphurous-acid 

 gas, carbolic-acid vapour, and the vapour of benzene — four materials very 

 dissimilar in chemical properties, but having a common hostility to low forms 

 of life. Chlorine, sulphurous acid, and carbolic acid are well known to have 

 such a property ; and, knowing that benzene is used by the entomologist for 

 killing insects, and having ascertained by experiment the potency of its vapour 

 for the destruction of pediculi, I thought it probable that it would also answer 

 our purpose. I then dressed with these four kinds of prepared cotton-wool 

 various suppurating sores, excoriations, and contused wounds, after washing 

 the surface with the corresponding lotion, or, in the case of benzene, with the 

 undiluted material. The result in every instance corresponded exactly with 

 theory. After about twenty-four hours' exposure at the temperature of the 

 body, the cotton-wool was found to have lost the odour of the antiseptic, yet 

 the blood, serum, or pus, as the case might be, remained perfectly sweet for 



* My friend Dr. Meredith, of the Indian Service, who attended Tyndall's first lecture on ' Dust 

 and Disease ', just after a visit to Edinburgh, where he had been greatly interested with the antiseptic 

 treatment, at once wrote informing me of this experiment, and asking if I did not think that cotton-wool 

 might be turned to account for excluding the causes of putrefaction from wounds — a suggestion which 

 I at once proceeded to act upon as above described. 



